A good selection of perennials provides an ongoing framework for the organic flower garden. Perennials are plants which flourish, then die back before re-establishing themselves in a seasonal cycle which should continue for at least several years. They can almost be considered permanent in cooler climates which provide favourable growing conditions. On account of this longevity, it is worthwhile preparing their ground thoroughly prior to planting. Most perennials benefit from well aerated soils which contain substantial quantities of thoroughly broken down organic materials such as compost, manure, and leaf mould.

Healthy juveniles are generally available as potted plants from organic nurseries and plant wholesalers. In temperate climates these can be transplanted to the garden throughout the year although spring and autumn are preferred.

While securing nursery stock will save time by enabling plants to establish themselves earlier, this approach can work out expensive when the garden is substantial and requires a large quantity of plants. In this case, an ideal alternative is to raise perennials from seed. Most gardeners choose to commence their seedlings in punnets. This will provide some protection against external uncertainties and can also assist the effective placement and arrangement of plants in planned flower beds.

For the inexperienced, it is sensible practice to visit and speak with as many experienced gardeners as possible. Ask them to recommend flowering shrubs and perennials which are well adapted to local conditions and exhibit some natural resistance against insect pests. These plants will be easier to raise and maintain organically, without resorting to chemical treatments.

Much of the effort needed to maintain decorative perennials is devoted to establishing a sense of order and structure. An excessively crowded flower garden is difficult to manage and may contribute to preventable problems. It is much easier to keep on top of things by digging out any spreading or poorly spaced plants. These can usually be divided and given to friends, or replanted in different areas of the garden.

Flowers should be removed as they fade. When seasonal conditions allow, most plants will produce a second bloom. Otherwise, it is common practice to cut them back to ground level. This removes opportunities for incubating disease or insect problems and encourages healthy growth and flowering during the subsequent season. In saying that, a few varieties of chrysanthemum should be left intact since they develop particularly attractive seed heads during winter. Among shrubs, hydrangea blooms should also be preserved to protect the following year’s growth.

In traditionally inspired flower gardens, annuals provide a decorative background which serves to highlight the presence of long lasting and permanent residents. In warm temperate climates, the majority of annuals flower within several months of sowing then commence to produce their own seeds before dying within a nine month period. Their lifespan however, is greatly determined by the local climate and growing conditions. In cool climates they can mimic perennials and last for several growing seasons.

More recently, popular annuals have been selectively bred for increased flowering and longevity. Most organic gardeners will grow a number of annual varieties, selecting them carefully for their versatility and natural resistance against commonly encountered disease and insect problems.

Flowering annuals should be applied creatively, perhaps in similar ways that a painter works with a brilliant palette of fresh colour. If the garden looks bare, annuals can provide some temporary cover while the slower growing permanent plants begin to establish themselves. Later on, annuals can be selectively planted to provide large masses, clumps, or sprays of colour which complement and enhance the permanent residents.

Don’t miss opportunities to grow annuals in locations where they are easily seen and enjoyed. Aim to plant the tallest annuals and perennials at the centre of flower beds with low growing varieties surrounding them. A simple border of flowers will decorate and visually uplift pathways, fences, and walls. They can be used to brighten verandas and patios or grown inside containers on a windowsill. Many annuals can be sown directly but most common varieties can also be purchased from nurseries as punnet stock.

In a manner similar to other fashion trends, these plants are marketed each season in a range of summer and winter flowering editions. Until recently, the readily available varieties of organically certified seedlings were plainly packaged and varied little from year to year. The current trend is to compete with the sales distribution of conventional seedling stock by increasing availability and including some additional marketing information to encourage sales.

When purchasing seedling stock, aim to obtain compact plants with healthy green foliage. Tall and straggly seedlings have probably been rushed ahead with fertilisers and growth promoting chemicals while those with yellowing leaves may be physically stressed. The ideal situation for most annuals is a well aerated soil with a sufficient amount of well incorporated organic material to hold moisture. Some varieties have strong preferences for full sun or partial shade, although many will accommodate either with little trouble.

Immature plants are often attacked by slugs, snails, and caterpillars. These can be controlled by physical removal and installing aromatic companion herbs such as chives, peppermint, and cloves.

Once they are transferred to their garden locations, flowering annuals should be carefully watched for signs of dehydration and nutrient deficiency. Because of their quick growth cycles and rapid responsiveness, experienced organic growers tend to use these plants as a barometer for conditions within the garden.

The maintenance of flowering annuals is relatively straightforward but potentially time consuming in larger gardens which contain a significant number of bedding plants. To develop attractively and exhibit their flowers to full advantage, some varieties require lots of minor attention throughout their development. This usually involves pinching back the growing tips to encourage the correct balance of concentrated vertical and outward spreading development. Fading flowers need to be periodically removed to encourage regeneration and dying plants will need to be removed and replaced.

When there are restrictions on the availability of gardening time, it is probably better to have fewer annuals and to consciously choose varieties which do not require a lot of shaping and have flowers which last well before drying out and separating neatly from their stalks.

From historical times to present, writers and artists have always sought inspiration amidst the strength and majesty of living trees. They comfort the soul, and quietly offer their reassurance during difficult times. An American Indian proverb describes them as our silent brothers, sharing the sacred journey of life. Whether chosen for their flowers, fruit, or foliage, trees are accurately described as framework plants. In this capacity they influence the visual and aesthetic characteristics of their surrounding environment. Above all, trees provide the sense of permanence which characterises an established organic garden.

Once established, many varieties of tree are low maintenance and provide an additional dimension to gardens, particularly those managed according to organic principles. Trees assume an important role in stabilising and sustaining the types of habitat most suitable for complex, productive ecosystems. During daylight, trees absorb carbon dioxide then release oxygen to the atmosphere. This occurs as a consequence of photosynthesis, a process to transform radiant energy into the sugars and other carbohydrates required to support plant growth.

Over the longer term, most tree species will benefit a soils nutrient profile by providing an abundance of leaves, twigs, and associated materials suitable for composting into the rich organic layer known as humus. The exceptions to this are the conifers, and certain species of fern which can acidify some soils to a level which prevents normal nutrient transfer and absorption. Spreading tree roots assist in the prevention of soil erosion and larger trees can protect flood prone land by storing large volumes of water in their roots and trunk. When planted strategically, trees may be used as an effective barrier against wind and noise. They also provide a protective shelter for many animal species, particularly birds, insects, small mammals, and reptiles.

For general categorisation, the term tree is most frequently used to describe woody stemmed plants of singular trunk, with a mature elevation of at least four metres. By contrast, shrubs are lower in height and may grow from multiple shoots or spread outwards from a foundation trunk. It is most important to select only healthy trees from an organically certified grower. Favour those with evenly proportioned branches and strong trunks. Try to avoid specimens with untidy or tightly packed roots, particularly those raised in disproportionately small containers. Reputable tree nurseries sell most of their stock as potted seedlings, and juvenile plants. With favourable weather conditions, container grown plants can be transplanted directly to soil as required.

Larger, bare root specimens are initially raised in commercial plantations. After several years they are carefully dug out then packed in a light peat moss or sawdust to protect their roots. This allows heavier plants to be transported without the attached bulk of soil or potting mixture. Bare root trees are only suitable for planting during their dormant winter phase. Prior to planting, they can be kept in a cool, sheltered place with their roots secured in several layers of hessian. Exposed roots are extremely sensitive and can be functionally damaged by rough treatment, sunlight, and exposure to excessive heat or dryness.

When planting trees as juvenile grafts or seedlings, the selection of an appropriate site requires sound judgement and planning. The important factors to consider include mature height, density, and spread of the branches and root system, along with the basic water, sunlight, and soil requirements of each particular species. Most trees require a decade or more to reach their mature size, making it difficult to predict their impact on the landscape and upon other plants and physical resources.

Prior to the commitment of planting, it’s important to spend a few hours researching the particularities of each selected species. Give careful consideration to potential drawbacks or problems that other growers have encountered. Tall species need plenty of clearance, so be certain to locate them a safe distance from overhead lines, dwellings, and other elevated structures. Those trees with vigorously spreading root systems need to be isolated from sealed water supplies. Several species of willow, poplar, and fig tree have been known to damage sewage and drainage lines by progressively invading concrete and ceramic pipes. In fire sensitive locations, there must be an appropriate clearance surrounding homes and other structures. Since eucalyptus oil is a volatile and flammable substance, these trees can combust explosively in a serious fire.

Like other plants, a number of common trees have the drawback of highly toxic leaves, sap, or berries. These are unsuitable for planting near schools, parks, and other public areas visited frequently by children. Similarly, there are varieties of eucalypt, conifer, and others that may shed tall branches unexpectedly. Mature trees with broadly spread foliage tend to cast dense shadows which can restrict opportunities for plants growing beneath. Deciduous trees have the advantage of providing welcome summer shade but will bare their branches over winter months, when the days are shorter and sunlight is relatively scarce. Fallen leaves can be raked into large piles and left to break down to valuable organic mulch which is fine enough to be raked directly into soil. Dependent on prevailing temperature and humidity, this process will require between twelve and twenty four months to complete. High quality leaf mulch is smoothly textured and dark brown or black in appearance.

Maintaining the natural fertility of soils is the basis for all organic practice, including the cultivation and preservation of shrubs and trees. The best soil for most tree species is a well drained composite of sand, silt, and clay particles. The drainage characteristics will be largely determined by the surface slope and the physical properties of the deeper subsoil layers. Before planting trees, it is recommended that surface layers of topsoil be enriched by the inclusion of compost and shredded organic materials. A rotary hoe is most effective for incorporating substantial amounts of organic materials at a depth beneficial for active tree roots.

Successful tree planting is dependent on careful preparation of the chosen site combined with the appropriate climate and maintenance during the establishment period. Immature trees rarely thrive in uncultivated soils, so it is essential to be generous with the spadework. The minimum requirement is a deep hole of sufficient diameter to contain all extended roots. Digging down to break the subsoil will improve the natural drainage of the soil. When removed from the hole, carefully pile each layer of soil to enable replacement in the same sequence as removal. This preserves structural integrity and natural drainage characteristics.

Once the site is prepared, the fledgling tree can be positioned carefully then lowered into the hole. Using the correct layer of subsoil filling, adjust the depth of the hole to enable the trunk to sit comfortably within the ground. Container grown saplings can be placed at the level of the old soil mark while bare root stock should be adjusted until soil just conceals the highest root buttress. When uncertain, it is preferable to plant slightly higher rather than lower into the ground. Root bark will usually adapt when exposed to the air, while the trunk bark is likely to rot once buried within the ground.

For their physical support and protection, immature trees require staking at the time of planting. Ideally, the stake will securely anchor the roots and base, enabling the upper sections of trunk to move with a transverse flexibility. It is the gentle but continual movement of the trunk in wind which thickens the base and contributes to a mature, well branched, and sturdy root system. Special tree ties or nylon stocking can be used to secure the tree against its support. Twine or wire should be avoided since they may cut or distort the trunk as it expands in growth.

Lack of sufficient water is the cause of most early failures in tree planting. After several weeks the immature roots should spread over the new ground in their search for water and soil nutrients. In the meantime, most saplings depend upon a combination of effective watering, excellent soil drainage, and some basic water conservation techniques. Effective watering penetrates the surface and encourages tree roots to become more efficient by branching deep and wide. Surface watering does not help the maturing plant establish itself sufficiently well to cope with prolonged dry periods and drought. It is better to avoid watering during the hottest parts of the day. Choosing cooler periods in the morning, late afternoon, and evening will help to prevent wasteful evaporation. Surface mulching with organically certified compost, leaf mulch, or woodchips is an excellent method for trapping and holding water that might otherwise evaporate or drain away.

There is no reason to chemically fertilise a newly planted tree. If the site is well chosen and prepared according to organic principles, the soil should be sufficiently enriched to provide the soluble nutrients, water, and microbes required for optimum plant growth and ecology. Established trees benefit from additional fertiliser, such as organic seaweed emulsion, or liquid worm manures. While the tree is less than two years established, it is helpful to use an organic fertiliser every spring. By concentrating these applications beyond an external boundary at least one metre distant from the trunk, developing roots will be encouraged to spread widely rather than settle in compact, inefficient clumps.

When grown according to their preferred climate and soil conditions, most mature trees contribute various qualities to their gardens without demanding any more than a basic schedule of maintenance. The established principles of organic gardening are ideal for ensuring the health and productivity of soils, and the plants which depend on them. Like all living organisms, individual trees will occasionally become subject to certain types of disease and parasitic attack. Some species are more vulnerable, and expert knowledge can play a significant role in the early identification and eradication of such problems. There are also a number of physical injuries which affect thousands of trees, stunting their normal growth, and restricting some of the anticipated benefits like organic fruit, flowers, and protective foliage. All physical damage should be treated as early as possible to prevent unnecessary complication.

Not all trees will withstand excessive exposure to strong winds. This is generally true of forest species accustomed to the protection of encircling companions. The signs of wind damage include bent or bowed limbs, torn branches, buttressed roots, stripped bark, and stunted growth. In serious cases, the tree may begin to slowly split down its trunk and will require major surgery or destruction. Pollution and salination of groundwater is of major concern in many countries. Trees need protection from toxic agricultural chemicals and hydrocarbon fuel contaminants including diesel oils, petrol, kerosene, and paraffins. Organic farming and horticultural practices are designed to establish healthy, contamination free soils and groundwater.

Even the most conservative estimates suggest that approximately thirty percent of marketable vegetable produce is lost each year due to poor handling and storage in the period following harvest. On a global scale this represents a significant quantity of food, enough to support very large populations such as China or India’s. In line with a general emphasis on sustainability, organic vegetable production should be dedicated to minimizing waste and inefficiencies associated with inadequate storage procedures.

Anyone who’s old enough might recall extreme shortages of fresh fruit and vegetables in Britain during the Second World War. Some popular historians attribute this to the breakdown of agriculture caused by labor and equipment shortages. I’ve recently conducted my own research and located material which challenges this viewpoint. During the early years of the war, agricultural production increased marginally in several important sectors. One of these was vegetables. Why then were so many children from London, Manchester, and Glasgow chronically malnourished and scurvy afflicted? It appears one of the most significant factors was a systemic failure to maintain effective distribution and storage for the produce grown in the majority of rural districts.

Local archives of farm records and correspondence frequently reveal the levels of difficulty and frustration experienced by commercial growers. In a letter to his uncle, Douglas Woodbridge of Surrey recorded the loss of his spinach and turnip crops. Several hectares of mature plants were ploughed into the fields while the remainder was sold locally as livestock fodder. He comments on the lack of incentives and support given to farmers in his district, particularly those experiencing difficulties holding or consigning their produce.

In more recent times, improved understanding of the physiology of fruit and vegetables has resulted in a range of storage and distribution procedures which can be applied to reduce the risk of substantial post harvest losses. Food technologists commonly refer to harvested fruit and vegetables as living structures. When described in this manner, we’re reminded that most produce continues metabolizing following detachment from parent stock.

Fresh vegetables absorb atmospheric oxygen and release carbon dioxide, water, and heat. Within individual cells the metabolic breakdown of stores containing starch, sugars and organic acids results in molecules of carbon dioxide and water. Once detached from parent stock, these progressive water losses cannot be replaced by the distribution of sap through interior vessels. In combination with the prevention of microbial and insect challenges, contemporary post harvest technologies usually aim to reduce the metabolic rate of stored produce. Several of these involve chemical substances or procedures incompatible with the environmental and health precautions of organic certification standards.

There are a variety of economical ways to store organic vegetables but the best approach will depend upon each particular variety and the season. The majority of root crops can be stored satisfactorily in cool locations which are well protected from sunlight. When grown in small quantities, root vegetables such as parsnip and turnip can be left in the ground until required. One traditional storage method which remains popular in some developing regions is the ventilated pit. Hard vegetables including potatoes, turnip, and yam are carefully piled inside pits carved beneath the elevated facades of terrace slopes, hillsides and other suitably drained locations. The interior is usually insulated with layers of straw then covered with dry sand or earth to protect the vegetables from frost and extreme weather conditions. Underground cellars were once widely popular as a practical means for securing below ground storage. The better examples provided ventilation openings which enabled the circulation and removal of excessive humidity.

Careful handling then storage will enhance the longevity and nutritional value of organic vegetables. Bacterial mould is more likely to develop on bruised and damaged vegetables, and can rapidly spread to affect others. For this reason, it’s important to inspect stored crops regularly and remove any that have started to decay. Optimum results depend upon selecting the highest quality vegetables and rejecting any which are bruised or blemished. Many of the microscopic organisms causing mould and other forms of decay are unable to penetrate intact exterior skin but will readily invade through swollen areas and cuts. The portion of skin surrounding the stem is a frequent point of entry for microorganisms. As a general rule the rate post harvest decay is decreased by low storage temperatures and humidity. The highly controlled environments designed for commercial storage may also restrict circulating oxygen and prevent natural ripening with chemical treatments.

Following a successful harvest, I make efforts to store my vegetable groups separately and always avoid storing any type of fruit with vegetables. A non-functioning refrigerator or chest freezer can make a useful storage vessel for garden fresh vegetables. They offer protection from light and the insulation helps to maintain relatively constant temperatures within. Adequate ventilation can be ensured by drilling small holes in the door or lid sealings. They are inaccessible to rodents so can be safely housed outdoors in dry sheds and other suitable buildings. Larger vegetables like pumpkin, marrow, corn, and potatoes can also be stored in clearly labeled wooden or plastic boxes. The red skinned and other pigmented potatoes are particularly long lasting and may be stored for up to one year. Well-ventilated containers will accommodate several layers when required. Since it is important to minimize contact during storage, each new layer should be separated from those below with sheets of corrugated cardboard or similar. Onions and garlic will also last a considerable time but need to be properly aired in string bags or hessian sacks.

Depending on their variety and physical condition, many organic vegetables will benefit from refrigerated or frozen storage. According to food experts there are few nutritional disadvantages associated with snap frozen vegetables or those correctly accommodated in refrigerated stores. Because vegetable varieties respond differently according to their physiology, it can sometimes be challenging to select refrigeration temperatures suitable for a range of seasonal and imported produce. Provided there’s no risk of cold injury, maximum storage life is usually obtained by approaching but not exceeding the freezing point of tissue. In vegetables not susceptible to cold injury, maximum storage life can be obtained by storage close to the freezing point of the tissue. By maintaining an even temperature around four degrees celcius the durability of leafy greens, peas, corn, and asparagus can be extended over several days despite fluctuations or extremes of local temperature. Given they’re in perfect condition, a wide range of organic vegetables can also be frozen for several months without losing their nutritional quality or flavors. To prevent scarring and discoloration, crisp fleshy vegetables like beans, cauliflower, and broccoli should be blanched in boiling water for sixty seconds before freezing.

Within a short period of time refrigerated cold storage may interfere with the overall quality and flavor of root and tuberous vegetables. Refrigeration tends to encourage the conversion of starches to sugar, resulting in vegetables with poor texture and less robust flavors. When stored at temperatures above fifteen degrees celcius, many potato varieties will exit their dormant stage and commence sprouting. This can usually be delayed by storage systems which avoid unnecessary light, humidity, and close proximity with other produce. Dependent on their codes of practice, some commercial distributors may apply chemicals or radiation to suppress sprouting in their potato consignments. Maleic hydrazide (MH), isopropyl-phenylcarbamate (IPPC), and methyl naphthaleneacetic (MENA), are all commercial sprout inhibitors. All of these chemicals are potentially harmful and remain subject to legal restrictions or total bans imposed by organic certifiers.

Just two blocks down from my daughter’s house there’s a small grocery store stocking an exclusive range of organically certified sweet relish, pickles, and salsas. I always purchase a few jars of their spicy vegetable pickle. It’s terrific for firing up a ploughman’s lunch. Before refrigeration, food preservation techniques were an essential component of household management. Given sufficient time, spare vegetables can still be transformed into a wide range of traditional and exotic accompaniments. Zucchinis, onion, carrot, beetroot, and many others can be gently simmered with vinegar, sugar and combinations of spices, apple, tomato, and raisins. When properly sealed in preserving jars, home made relish and chutneys store on the shelf for up to twelve months. From my experience, food preservation tends to encourage resourcefulness and reduces the potential for waste. Produce falling below a premium standard can also be processed into juices or purees then frozen for up to one month before being used in soups and other recipes.

Towards the end of last summer, I harvested a bumper crop of organically grown peas. They were extraordinary in taste and quality. For several weeks I gathered them before dawn then packed them inside raw calico bags which stacked neatly inside the crisper section of my old twin door refrigerator. I offered them to relatives, friends, and neighbors.  Apparently there was no shortage of families who appreciated receiving small packages of freshly harvested garden peas. After my initial distributions I received a polite telephone request from a local restaurant. One of their patrons mentioned my crop of peas and the chef was hoping to obtain some for his special minestrone. No problem, I agreed.

The following day’s sunrise caught me unprepared. I was filling the bags and steadily loading my wheelbarrow when the eastern horizon expanded with the most brilliant glow of warm orange light. I walk to the edge of my garden, surveying and appreciating all that nature provides. Dogs are barking somewhere in the distance but my thoughts swirl with the songs and memories of my childhood, this perfect moment.

Harvesting is potentially the most enjoyable and rewarding of the activities associated with organic vegetable gardening. By fulfilling the need to provide ongoing food and sustenance, the harvest was originally experienced as a time of celebration and healing. Amongst traditional societies, there are numerous examples of harvest rites and celebrations which are usually associated with the religious and spiritual practices of their people. In Western Europe and North America, for example, the concept of Halloween extended from the combination of agricultural and religious ceremonies. These were established to accompany the annual harvest of grain and vegetables, before onset of the northern winter. Native tribes of Canada and North America frequently included dimensions of renewal and healing to their traditions of harvest celebration. Contemporary scientists have also reported the positive effects of gardening, including increased levels of serotonin and endorphin generated around the time of harvest. These are natural chemicals released in the brain to promote relaxation and a deep sense of well-being.

The optimum time for harvesting vegetable produce varies according to the influence of soil condition, seasonal factors, and personal taste for the flavor and texture characteristics of individual varieties. In many instances, the timing will be influenced by the metabolic rate and storage characteristics of individual vegetable types. Immature seeds and legumes like sweetcorn, fresh peas, and beans contain high water content and an elevated metabolic activity. These vegetables are generally harvested before their sugars are converted to additional starch. Vegetable varieties consisting of edible flowers, buds, and leaves can also have high metabolic activity and may be susceptible to mould and bacterial damage when their harvest is delayed. Most of the root, tuber and bulb vegetables have slower metabolic rates and are less likely to require early harvesting. Beetroot, carrots, onion, potatoes, parsnip, swedes, and turnip are classified as non perishable, and can be stored for prolonged periods if required.

Inexperienced growers tend to focus on the harvesting schedules published in popular gardening books and magazines.  The majority of winter vegetables should be picked towards the latter stages of their growing season. This is certainly true however each crop is unique and experienced gardeners must eventually develop strategies for consistently determining this point. I usually depend upon the physical properties of my produce. I’m more than satisfied with vegetables exhibiting a pleasing combination of color, firmness, and size. I also know that some gardeners employ scientific measures. I’ve listened to experts who use special instruments to evaluate the electrical and light transmittance characteristics of their vegetables. There are standardized tables which determine levels of maturity and ripeness according to these measurements. Less accurate comparisons are sometimes based on the chemical composition or respiratory behavior of vegetable samples.

Summer vegetables are frequently harvested before the onset of physical maturity. Commercial crops of sweetcorn, beans, and peppers are influenced by contemporary food styles as many distinguished chefs and providores demand the sweet taste and crisp texture of immature vegetables. Home growers and hobbyists can choose to ignore current fashion, although many prefer harvesting early to commence new crops or to encourage additional vegetables on plants which produce throughout the season. There is also an argument that early harvesting discourages the onset of troublesome plant diseases like sclerotinia, canker, and wilt.

The majority of commercial growers prefer harvesting their vegetable crops with high water content. This ensures optimum weight and appearance, particularly for the leafy greens which respond most rapidly to changes in their external environment. In some instances, maximum water content is encouraged through the use of chemical solutions, generally resulting in a bland or neutral taste. Skilled organic growers usually attempt to manipulate their watering to achieve maximum flavor in combination with high water content at the time of harvest. By carefully restricting watering throughout the early and middle stages of growth, vegetables are encouraged to increase the flavor characteristics determined by local influences such as climate, soil, and planting arrangements. When watering is increased during the final weeks of growth, most vegetables hold the additional fluid within their cells at the time of harvesting.

Efficient harvesting depends upon an ability to reject poor quality produce in coordination with handling and storage techniques which maintain an optimum standard of quality. In the first instance, harvested vegetables must be healthy and fully intact. This implies the absence of any symptoms relating to disease, pest infestation, or the physical signs of damage including bruising, cuts, and swelling. There are several reasons why damaged vegetables should always be discarded. Mechanical damage can easily distort the protective function of outer tissue layers, resulting in accelerated rates of gaseous exchange and water loss. Surface defects can also permit access to bacterial decay and disease causing microorganisms. Once detached from their parent plants, the capacity for wound healing and recovery is greatly diminished or negligible for most vegetable varieties.   

Some varieties of vegetable are particularly susceptible to water loss during the timespan between harvesting and secure storage. Water loss can occur through the combination of accelerated metabolic activity with a hot and dry atmosphere. Under such conditions, it is possible to lose approximately ten percent of the harvested weight for a perishable crop within several hours. This generally results in severe wilting and decreases the overall crispness and palatability of the produce. In the absence of protective measures, the rate of water loss depends primarily upon the ratio of surface area to volume. Leafy vegetables like spinach, for example, have large evaporative surfaces which suffer greater losses per unit weight than root vegetables like parsnip or swede.

Most commercial producers make considerable efforts to protect their vegetable harvest from water loss and several of their techniques may also apply to small scale organic growers. To ensure milder conditions, many crops can be harvested at night or early in the morning. The rate of water loss can also be reduced by providing physical barriers which limit the free circulation of warm air. These employ a variety of readily available materials including polythene films, fiber cartons, and sawdust. With current improvements in handling and storage techniques, it is now considered beneficial to quickly reduce the temperature of vulnerable vegetables at the time of their harvest. This can be facilitated with mobile chillers and air conditioned storage bins. Sometimes described as precooling, the technique is widely employed for highly perishable varieties of lettuce, broccoli, cauliflower, peas, and asparagus. Precooling restricts the rate of water loss, prevents undesirable changes in color, and protects important nutrients like vitamins C, A, and folic acid.

I have a dear old friend, Thomas, who raises organic vegetables in timber barrels. Several decades ago, well-used barrels were frequently discarded from the larger vineyards and distilleries or sold to gardening enthusiasts for a modest sum. Nowadays, the use of wooden barrels is greatly diminished as inexpensive alcoholic beverages are increasingly stored in stainless steel kegs. Consequently, the few wooden barrels currently available have become sought after items. They’re typically sold by outdoor design centers and antique dealers for upmarket prices. My friend recalls two men offering several thousand dollars for his collection of barrels. It was Easter Sunday and they were offering cash, he explains. They had their truck with them and they seemed pretty confident about purchasing his barrels. What’ll you do with them? inquired Thomas. Saw them in half, varnish them, and mount them on decorative stands. Sell them on the internet. On the internet? Thomas repeated. Yeah, they confirmed, decorative containers are popular on ebay.

The main challenge for the gardener interested in container grown vegetables is to select suitable varieties and to accommodate their individual requirements for space, water, sunlight, and nutrients. Container raised vegetables are susceptible to crowding, more so than those planted in open ground. Deep and spacious containers like those wooden barrels are ideal for growing small quantities of organic vegetables, particularly the green leafy varieties and compact growers like cherry tomatoes, and snow peas. Leafy vegetables like spinach or silverbeet grow surprisingly quick and even regenerate themselves after picking. Potatoes can be grown in troughs or drums which are simply emptied at harvest. There are miniature varieties of carrot and other root vegetables which have been refined for container growing. Containers are inappropriate for several classes of vegetable. Heavy feeding plants like corn are better served in open ground and the larger spreading vines like pumpkin, marrow, and aubergine will struggle to reach their potential when planted in containers.

When grown in open ground, vegetables can extend their roots over distances to obtain sufficient water in dry conditions. Because of their restricted root systems, container-grown plants require more frequent watering. At the peak of a dry summer, this may increase to several times each day. Automatic sprinkling systems can be programmed to deliver measured volumes of water at intervals throughout the day and evening. These units are extremely valuable in gardens supporting a large number of containers. The down side associated with frequent watering is the potential for drainage problems combined with a continual washing away of water-soluble nutrients. Providing regular replacement in the form of a liquid plant food can usually offset the loss of nutrients. The best organic products include seaweed extracts, liquid manures, and milder solutions brewed from nettle or comfrey leaves. While expensive, commercial organic supplements improve the overall quality and yield of container-raised produce. These should be carefully diluted according to each manufacturers recommendation. Excessive concentrations cannot be absorbed and will eventually damage root structure and function.

In the absence of good drainage, planting containers may eventually become waterlogged, damaging vegetables by restricting the uptake of oxygen from their roots. Drainage is determined by the availability of porous channels which absorb then direct water towards the base. Upon reaching the base, excess water is encouraged to drain externally from the container. Good drainage can be assisted by using quality organic potting mixtures, above a base layer of scoria or ceramic and by ensuring that pots and tubs have several drainage holes that are at least two centimeters in diameter. Most garden soils tend to compact with frequent watering so are not recommended for container planting. The best potting mixes contain fibrous organic materials that hold an even dispersion of moisture and air pockets plus nutrients to support plant growth. The mixture must also be sufficiently dense to support the vertical growth and weight of plants. For growing vegetables, my friend Thomas uses an organic potting mix combined with sandy loam in approximately equal quantities. He completely replaces this growing medium after each crop of root vegetables. For his tomatoes and leafy greens, he generally replaces this after harvesting a second or third crop.

The metabolic rate of all green plants is determined by the availability of light and heat. There is quite a bit of variation in the optimum sunlight requirement for the different types of vegetable which are commonly raised. Spinach, for example grows happily in restricted sun or partial shade whereas most tomatoes require direct sunlight for at least four or five hours on average per day. Most container-grown vegetables require good ventilation and at least several hours of sunshine each day. Their location must be carefully chosen to avoid difficult and extreme weather conditions. Enclosed patios are usually suitable but open and elevated apartment balconies are often subject to extremes of heat, cold, wind, and rain. While the Mediterranean or European tradition for growing vegetables and herbs on raised balconies is a cultural tradition, there is a potential safety hazard when heavy planting vessels are positioned on elevated surfaces. Call me anxious, but I cannot avoid checking upwards on visits to Spain and southern Italy. My friends laugh because I still grab every opportunity to browse around the fashionable terraces of Messina and Palermo.

Now those ebay entrepreneurs were pretty keen to purchase old Thomas’s barrel collection. They added an extra hundred to the original offer. Thomas admits being tempted. The barrels were pretty old, he says. He thought about raising vegetables in deep acrylic pots. In the end, I couldn’t, he reveals. You’d become attached to the natural timber? I ask. Yeah, I suppose so. Those barrels are the functional elements of my garden and they were planning to cut them longitudinally. Shallow trays for temporary flower displays? He scratches his head with disbelief. Their shape is kind of important to me, he asserts. I admire rounded things with pleasant curves. Like those old Buick passenger vehicles of the nineteen fifties. You don’t interfere with a brilliant design.   

Developing then pursuing a well considered plan is the best approach for achieving a satisfactory outcome. Expectation needs matching against ability and opportunity, even for low key activities such as organic vegetable gardening. The first stage of planning considers each expectation commencing with the broadest brush. What can be achieved? The most restrictive expectations are based on measurement. A certain volume, or weight each week, then a combined target for the end of the season. Commercial organic growers must operate within such narrow economies but can be challenged by uncooperative weather cycles and unpredictable events. Recreational gardeners can set a more flexible course, one that aims to include both functional and pleasurable aspects of their garden.

Increased choice

It is surprising, how many gardeners will grow too many vegetables, even those they don’t particularly enjoy eating. Thankfully, we are no longer restricted to traditional options like cauliflower, turnips, and cabbage. There is a much wider range to choose from, including stir fry greens, radishes, and peppers originating from Asia, South American and Pacific sweet potatoes, plump Mediterranean aubergines, and okra from the Indian subcontinent. To keep things interesting, it is a great idea to supplement a small selection of well known vegetables with at least one exotic species each season.

To realise their optimal nutritional benefits, fresh vegetables should be consumed within a few days of harvesting. Careful planning helps maintain a continuous and steady supply for the kitchen table. Will there be heavier demands through holiday periods, festivals, or religious celebrations? A calendar record of the best (local) seasonal produce will help to establish correct sowing dates. Always work backwards from the date that mature crops are needed.

Nutrient focus when space is limited

When garden space is restricted, it makes sense to concentrate on a small selection of plants that can provide a balanced range of vitamins and other essential nutrients. Leafy green vegetables like spinach, silverbeet, and beetrot tips are the best providers of vitamins A, C, and minerals like iron, calcium, and selenium. Brussel sprouts, broccoli and kale are excellent additional sources of vitamin C. For the B group vitamins a combination of potatoes, beans, pumpkin, peas, and sprouts is appropriate. This group needs to be further supplemented with a varied diet containing nuts, mushrooms, brewers yeast, pulses and whole grains. Modest amounts of vitamin E is found in most leafy greens but the main sources of this important nutrient are the cold pressed vegetable oils, avocadoes, apricots, and wheatgerm.

Random planting may be advantageous

Vegetable gardens can follow the traditional pattern with a designated plot and plants arranged neatly in rows. This requires some extra preparation and maintenance but enables early growth to be carefully monitored. Weaker plants can be periodically removed to reduce the competition for light, moisture, and soil nutrients. Alternatively, vegetables can be grown randomly throughout the entire garden. This is a more natural situation and tends to favour vigorous stock and excellent produce. Weak or substandard vegetables will eventually be overwhelmed by the healthier plants surrounding them. A random planting offers better protection against insect pests, mainly because the attractive signals are weakened and the increased distances between each plant deter colonisation.

At the planning stage, vegetable gardeners need to consider the separate conditions required for annual as opposed to perennial plants. Annual vegetable crops, such as carrots, broccoli, and potatoes, need to be rotated to a different growing space each season. This procedure helps to prevent soil disease, pest infestation, and enables soil replenishment during a fallow period that is scheduled between each sequence of crop rotation. Perennial vegetable crops like asparagus continue producing for a second and third season. They tend to be low maintenance plants with new shoots growing quickly to replace any stalks that are removed. When appearances are important, it may be worth checking the eventual height and spread of new seedling purchases. Very tall plants may look out of place among rows of shorter ones; they may also require some staking support as they mature. Fast growing vines like cucumber, choko, and squash appear unruly when they’re allowed to spread over pathways and walls.

Involve others

The planning and preparation for an organic vegetable garden can be challenging and enjoyable when undertaken together by a family group or friends. The task may even require some creative scheduling and a diplomatic chairperson or moderator. Participants provided with opportunities to express their needs and preferences from the beginning, are more likely to remain enthusiastically involved in the day to day running of the garden. It is also important to include everyone’s favourite dinner vegetable. Children who find cooked vegetables unpalatable can be encouraged to try garden produce in simple salads. These should focus on a selection of tasty ingredients that readily combine in patterns of bright, inspiring colour. Sweet baby carrots, lightly steamed corn, fresh peas, and grated beetroot rank among the best choices

When I commenced my apprenticeship, there was a strict emphasis on vegetables, fruit, and ornamental trees. Despite my early enthusiasm for flowers, shrubs, and lawns, I was advised to concentrate on the vegetables.

I still recall the words of the Head Gardener at the time. “Learn to grow a decent vegetable and you’ll have earned the respect of your trade”. Very outdated I suppose, but wait, there’s more. On the third Saturday of each month a formal dinner was held. We were given the weekend’s leave but the Friday beforehand was dedicated to finishing touches on the grounds in addition to a selective harvesting of seasonal produce. We literally filled the kitchens with an assortment of our best vegetables. They were carefully laid on rough oak tables. Onions, carrots, parsnips, and string beans so crisp they virtually exploded when you snapped them apart. Butter squashes with their delicate white flowers attached, new potatoes, celery, aubergines, and spinach. Deep golden pumpkins and cream tinted cauliflowers. Like a still life painter, I was entranced by their shapes and colour contrasted against those ancient oak tables.

Over subsequent years, I managed to gain some insight on organic principles and many of the practical applications associated with vegetable gardening. While there are several important rules which should be observed, it is my belief that too much technical information can quickly confuse and restrict the novice gardener.

I often introduce my gardening discussions with first hand accounts emphasising the intrinsically human qualities of this activity. There is little doubt, for example, that an ability to supply foods from the garden can generate a complex sense of achievement and security for many individuals. My parents maintained a productive garden which provided our family with plenty of fresh vegetables during and immediately after the Second World War. These were challenging times in Britain, and families like my own were often dependent upon home grown vegetables.

Today, self sufficiency remains an attractive concept, one that is frequently associated with organically grown produce. The degree of planning and effort required to produce the variety and quantity of fresh vegetables to support a large family is considerable and would probably discourage many enthusiastic beginners. A more realistic expectation might be the reduction of weekly grocery expenses in addition to regular supplementations of fresher and superior quality vegetables compared with those available from local supermarkets. Whatever the quantitative outcome, there is always a quiet sense of fulfilment when home grown food is delivered to the table. Maintaining this positive outlook helps to overcome minor setbacks and ensures that growing vegetables becomes an enjoyable rather than laborious effort.

According to medical and lifestyle surveys, there is now a widespread tendency for modern families to miss out on the nutrients required to sustain their long term health and wellbeing. There are numerous reasons why growing vegetables organically, at home, makes good sense. Consider the superior nutritional content of organic produce. Combined with the fact these foods are pure and wholesome, with no genetic tampering or chemical residues, home grown organic vegetables are the ultimate prescription for good health, vitality and longevity.

As a bonus, these nutritional factors are coupled with convenience. Once the organic vegetable garden is established, it’s possible to maintain a continuous supply of seasonal produce. When your basic ingredients are readily available, it’s much easier to prepare a range of nutritious and time efficient meals. Garden fresh salads in spring and summer then rich vegetable soups, pasta, or casseroles in autumn and winter.

Gardeners can also receive additional health benefits from the gentle physical exercise required to look after their plants. The amount of exercise depends upon the size of the garden, soil structure, and the types of vegetable being raised. Careful planning is of course essential to reduce unnecessary work for individuals with strict limits on the amount of time available for gardening activities.

It’s a fast paced world now and many individuals are restricted by their daily schedules. I’ve met plenty of people who commence their days at six in the morning then work steadily until ten in the evening. While establishing a large organic garden might be unrealistic under these circumstances, there is every reason to attempt a modest vegetable plot. During tenure with my local organic gardener’s society, I received correspondences from several individuals who described their personal satisfaction and sense of accomplishment as gained from their gardening activities. In reviewing these, I remain convinced that personal benefits are rarely specified by the number of hours allocated to a garden, or the volume of produce generated. Here’s Mr J’s experience. (I obtained his permission to reproduce the following) 

I’ve never considered myself the gardening type. Until recently, my life was devoted to a career which provided adequate social and financial incentives. I use the term adequate to emphasise concerns that my life somehow lacked a sense of balance. As a younger person, I pursued a competitive interest in rugby and maintained various recreational pursuits with close friends and family members. At a certain stage, the mental and physical demands imposed by my career forced me to focus inwards. By the time I reached forty, my schedule involved extended office hours and regular meetings abroad. I spent less time at home and began to lose intimacy with my family. I was constantly committed and never available. The pattern continued for nearly twenty years, before an unexpected event provided me the opportunity to re-evaluate my goals. My firm’s corporate sponsor was accused of tax evasion and other acts of financial impropriety. During an enforced absence from work, I became increasingly frustrated and anxious when my name was linked to false and damaging allegations.

My correspondent describes his disillusionment with the corporate environment before introducing the topic of gardening.

I waited near the far end of my section holding the spade while it rained steadily from heavy grey skies. A chorus of internal doubts encouraged me indoors. I nearly succumbed to the repetitive comforts of my newspapers and telephone. The rain eased slightly so I commenced digging the earth with the spade. The freshly broken soil was dark like Belgian chocolate. I crumbled a small clod between my fingers and it immediately stained them.

With his hands already dirty, it wasn’t long before Mr J ventured into the realm of organics. He obtained a newsletter from his local organic society and borrowed several books on soil management and vegetable gardening.

Upon planting my initial crop of vegetables, I was overwhelmed to encounter the generous support and advice of local gardeners and society members. I attended several society meetings and found myself participating in topical discussions about the advantages of organic whole foods, fair trade policies, and the long term sustainability of organic production methods. It wasn’t long before I found myself absorbed in the concept and principles of recycling and self sufficiency.

He goes on to describe a positive resolution to his career difficulties and the subsequent decision to establish new priorities in his life.

I rationalised my current situation and decided to undertake a part time consultancy role. This enabled me to work from home to a large extent and provided more time for previously neglected leisure activities like sailing, golf, and the occasional cross country hike. My organic vegetable garden sustained me through a difficult period so I was more than pleased to allocate several hours each week toward its maintenance.

The next passage illustrates that the benefits were largely independent of his overall efficiency and volume of production.

Upon demonstrating my capacity to produce a small selection of fresh vegetables, I was tempted to increase the size of the garden. After some reflection, I decided not to. The positive outcomes were already substantial so there was no immediate incentive for me to raise the stakes, so to speak. My vegetable garden provided valuable lessons regarding the integrity of physical effort and modest achievement. Since undertaking board certification, my entire career had depended upon establishing a reputation based on overstatement and exaggeration. This was continuously reflected in a lifestyle of excessive consumption and accelerated ambition. Organic gardening provided me with sufficient space to discover alternative inspirations.

Mr J describes a renewed pleasure in simple events. He finds himself breathing fresh air, mentally focused and well prepared to appreciate the seasonal influences, and subtle rhythms of nature. This new perspective on life encourages him to rest adequately and replace his stressed out eating habits with relaxed dining and wholesome meals. He concludes his correspondence with an observation on gardening’s impact upon his personal relationships.

My wife still teases me about the organic society, although she’s quick to admit that gardening helped me become a nicer person. I rarely experience anger these days, and my friends have noticed the difference. At work, I’m more patient with clients and have improved my ability to evaluate outcomes from their perspective. I’ve become less hostile on the road and have even stopped swearing at parking attendants.

And the postscript?

My son lives abroad and rarely contacts us. Yesterday I received a call several hours before dawn. He was thinking about planting some asparagus and wondered if I could provide any helpful advice. I laughed then told him to make sure the tips were pointing towards the sky.

Whenever possible, organically grown herbs should be eaten fresh from the garden, with minimum processing. This helps to ensure that beneficial nutrients get delivered to the body without degradation or unnecessary contamination. The basic rule for storing and preserving herbs is to start with the finest quality seasonal produce available. By establishing healthy soils and promoting a natural diversity of species, the experienced organic gardener has a significant capacity to influence the quality of their herbal produce.

When purchasing herbs for storage, try to obtain them directly from certified organic growers or local wholesalers who support the organic food industry. Preference vendors who replenish their stocks regularly, and avoid those who depend heavily on refrigeration or out of season lines. Discerning consumers will be interested in obtaining herbs rich in nutrients and the complex plant oils which provide their distinctive culinary flavours and aroma. As a general guide for selecting fresh herbs, search for those which appear darker in colour and those with smaller leaves. With the exception of basil and coriander, it is worthwhile avoiding specimens with bright and luxurious foliage. The most visually appealing herbs are often those which have been grown hydroponically or in fertiliser enriched soils. In both cases, the plants tend to develop high water content but seem to lack any significant concentration of the valuable plant oils.

After harvesting or purchase, try to handle the herbs as infrequently as possible. If they are to be stored for a short period, avoid washing, scrubbing, or separating bunches. Root herbs such as garlic, ginger, turmeric, and sarsaparilla need to be stored in a dark, cool, and dry location. If they are thoroughly dry, leafy herbs can be wrapped in paper and stored in the lower compartment of the fridge. Alternatively, cut the ends off their stalks then float small bunches in quarter filled jars of water. When placed inside the fridge, floating herbs should stay fresh for several days. Once the foliage begins to curl replace the water and discard any damp stems.

Tough herbs like rosemary and thyme last better than delicate ones like coriander, dill, and basil. A useful method for storing soft leaved herbs is to freeze them. They can be stored whole in labelled freezer bags or finely chopped in a blender then filled into ice cube trays. Once frozen, the cubes are a convenient substitute for many dishes which require the intense flavours of fresh herbs. With experienced chefs, it is common practice to create rich herbal stocks before reducing these to approximately one third volume then freezing in ice cube trays.

This approach enables the creation of blends which will provide the structure of both traditional and innovative dishes.  On separate trays, petals from edible flowers such as rose and nasturtium can also be combined with fresh mint leaves to provide a decorative and flavoursome garnish for summer drinks.

In earlier times, a considerable amount of creativity and effort was devoted to food preservation techniques. Country and suburban pantries were well stocked with a range of oils, vinegars, and preserves. Many of these were enriched by the flavours and nutritional qualities of organically grown herbs. White and red wine vinegars can be infused with aromatic herbs such as organically cultivated thyme, basil, fennel, and dill. Simply place a few leafy stalks into a sterilised vacuum jar then fill completely with vinegar before securing the lid. Allow the jar to stand and settle on a warm windowsill for several days. If desired, the vinegar can be filtered to remove sediment; otherwise the herbs should be left to release their flavours gradually to the vinegar solution. After seven days of warmth, transfer the vinegar to a cool and dark location where it should keep without spoiling for up to twelve months.

Many herb varieties are suitable for infusion within cold pressed organic vegetable oils. These can be chosen for their individual qualities or combined to create subtle and harmonious blends. Because high quality oils contribute their own distinctive flavours and consistency, it is important to maintain and enhance these by avoiding sharp contrasts or competing flavours in a herbal infusion.

One of the easiest infusions for the beginner to master requires fresh flowering herbs such as chamomile, chives, nasturtium, or thyme. Use a mortar and pestle to grind approximately one hundred grams of flowers and foliage from one of these species. Pack the processed material into a sterilised one litre jar then fill completely with a cold pressed olive or grapeseed oil. Once the jar has been carefully sealed, place it in a warm shed or drying cupboard. Shake occasionally but leave in the shed for approximately one month before straining and transferring to small jars or bottles. These can then be used immediately in cooking or carefully stored in a cool and dark location for up to twelve months.

Another method for capturing the flavour of dried herbs is to combine them with crystals of raw organic sugar or sea salt. Both substances absorb the natural oils and culinary flavours of many popular herbs. Mix the salt or sugar crystals with an equal volume of dried herb and mix well. The salt and herb mixtures should be baked on low heat for fifteen minutes on an oven tray. The traditional favourite is garlic salt, although chives, oregano, thyme, parsley and rosemary are all suitable. Sugar and herb mixtures need to be left in a sealed jar for several days before sifting to remove unwanted herb particles.

To add a subtle but memorable flavour to cakes, drinks, and desserts, try using a raw organic sugar flavoured with lavender blossoms, aniseed, mint, marigold or rose petals. Freshly picked and dried herbs can also be added in significant quantities to home made sauces, preserves, and salad dressings. A crab apple jelly with lots of fresh mint makes a delicious accompaniment to roast pork while cranberry sauce has additional depth when flavoured with organic sweet basil instead of sugar.

One of the most popular methods for preserving organic herbs is slow drying. When executed correctly, dried herbs do not lose their flavour, and in some instances it is said to improve. The stems of freshly picked herbs are first gathered together then secured tightly with twine to create small bundles. Traditionally, they are suspended upside down from rafters inside a well ventilated shed. The key requirement is a sufficient airflow to enable the herbs to dry thoroughly and evenly.

It is not good practice to dry herbs in direct sunlight or locations where the temperature exceeds thirty degrees Celsius. Under such conditions, a percentage of the volatile oils will evaporate into the atmosphere, compromising the potency and flavour of the dried product. Due to their humidity and heat, working kitchens are rarely suitable for drying purposes.

Depending upon their situation, airing cupboards, attics, and basements may be appropriate. The leave will be sufficiently dried in approximately two weeks, when they should feel crisp to touch. Remove carefully from the stems and gather into airtight containers. Hopefully the dried leaves will reveal green tones, a reliable indication that most of the plant oils have been retained. The airtight containers should be stored in a dark cupboard or pantry shelf where they should last for at least twelve months. 

Until recently, there were limited interactions between the cut flower industry and the organics movement. With the exception of dedicated plant breeders, the mainstream and popular flowers were largely grown in chemically treated soils with the assistance of toxic insecticides and spreading agents. In the flower plantations of developing nations, many of these materials are applied so indiscriminately that there is an adverse impact upon the local environment.

There are international health surveys which detail neurological and respiratory problems caused by elevated levels of chemical exposure. With the knowledge that some overseas flower plantations utilise child labour, the ethical consumer is obliged to consider purchasing an alternative product. If requested, reputable florists can provide flowers which were raised organically, in healthy soils. These will often be sourced from local producers who specialise in growing small quantities of native or well acclimatised plants. Due to variable demand, consumers of organically certified flowers should be prepared to pay higher prices and to accept a modest range compared with those grown conventionally.

The obvious alternative to cut flowers is an abundant supply of living blossoms. These can be planted as decorative ground cover, feature items, as potted specimens, and indoor arrangements. It’s only a decade ago when it was difficult to locate good quality nursery stock with organic certification. This is no longer apparent, since most popular flower varieties can be purchased directly online from organically certified plant breeders. Many of the specialist plant societies now contain members dedicated to organic principles. In open competition, organically grown orchids, roses, and tulips, all compare favourably against their rivals. While conventionally grown specimens produce large flowers which are brilliant in colour, they sometimes lack the genuinely healthy appearance and smell of organic flowers.

Flowers have the ageless appeal of luxury and sensuous pleasure. During certain periods of human history, flower gardens were perceived as the exclusive privilege of ruling classes. While peasant farmers toiled for humble grain crops, aristocratic overlords developed private estates decorated with rare and exotic blooms. In Victorian times, the art of floral arrangement was developed into an elaborate and ritualised form of social communication. Today, flowers continue to provide symbolic meaning at significant occasions such as weddings, funerals, christenings, and remembrance ceremonies. A North American study investigating links between flowers and life satisfaction found that flower recipients reported feeling less depressed, and received a boost in their self esteem scores.

Choosing to grow flowers is the surest way to invite an additional dimension of form, brightness, and fragrance into the organic garden. A selection of flowering annuals and perennials can be tailored to suit almost any garden situation. They are widely used to develop the shape and structure of a decorative garden. Flowers can provide definition for selected areas, or draw attention away from others. With careful planting, they will influence the perception of distance, making an area seem larger or smaller than it actually is. A warm colour scheme with arrangements of red, orange, yellow, and gold flowers is invigorating and cheerful but tends to advance toward the eye and make an area appear smaller.

Cool schemes with lots of blue, green, purple, and violet flowers are calming and reflective. These colours retreat from the eye and make an area appear more expansive than it actually is. Flowering plants should be chosen for the shape and texture of their leaves, perhaps developing some interesting contrast between broad and coarse as against fine and feathery foliage types. The most appropriate selection will also depend upon coordinating appropriately with the colours, shapes, and textures of nearby buildings, pathways, fences, and other decorative features.

I must admit that it has taken me a long while to be convinced of the benefits of soil testing. When I started out, most of the established gardens were resisting the obsessive wave of soil analysis which swept across the agricultural and commercial horticultural landscape. There were scientists and graduates from the universities wanting to help farmers and growers by analysing the chemical and physical properties of their soils. Several times each year, technical representatives from the emerging chemical and agricultural corporations would visit major farms, sporting grounds, and established gardens throughout the country.

Around this time, I lived and worked on a private estate and was on one occasion harassed by a foreign gentleman seeking to evaluate the nutrient composition of our soils. With no appointment, he proceeded to remove a hand auger and various sampling apparatus from his illegally parked vehicle. I correctly informed him that he would need to seek permission from the landholder. He provided me an expression of disgust interspersed with several volleys of debate. I directed him towards the gate and he drove off in an unnecessarily excited state. The following morning, I happened to be draining a pond near the boundary of the estate when I captured a glimpse of his vehicle partly concealed behind a mature stand of oak.

I eventually located him collecting soil samples among our native ornamentals. I enquired if he had contacted the landholder and he grunted in the affirmative. Upon checking, this was patently incorrect. I was subsequently advised to contact the police and have him removed as a trespasser. That’s just personal anecdote, of course. Perhaps somewhat irrationally, this incident prejudiced me against soil testing and soil testers for many years. More recently, I have encountered numerous scientists and technicians who undertake soil analysis and provide recommendations in a form which is entirely compatible with my organic and holistic approach to gardening.

Many gardeners find it helpful to access details about the chemical and physical properties of their soil. Basic soil testing kits can be purchased from garden retailers although the laboratory based testing conducted by professional firms will provide significantly more information. In addition to pH analysis, these are likely to include data relating to the soils texture, amounts of organic material present, availability of major and minor nutrients, plant toxins plus a schedule of recommendations and corrective measures. Whenever possible, it is better to choose an analysis that is specifically intended for organic growers. This type will concentrate on the quality of the organic material (humus) and the health of soil organisms required for optimum fertility. They should also provide recommendations based on correcting problems or deficiencies with organic fertilisers and supplements.

Soil testing and analysis is necessarily complex due to the range of physical and biochemical properties which influence fertility and manageability of the various soil classifications. I’m informed that each component of a comprehensive soil test has certain limitations and a predictable margin of sampling error. Most of the conventional sampling techniques require small amounts of soil to be physically removed from their original locations. By removing soil, there is disruption to the structure. This disruption inevitably contributes to alterations in particle distribution, temperature and moisture profiles, along with the complexity and distribution of organic substances and microbial organisms. This means that accurate analysis depends upon comparing results from many individual tests and removing extreme measures to arrive at an averaged or approximate view of soil condition. Understandably, this is an area for university graduates or gardeners particularly keen on mathematics and statistics.

The pH analysis of soil provides a measure of its tendency toward acidity or alkalinity. This characteristic varies from region to region depending on local soil chemistry, rainfall and climate patterns. Most soils in coastal rainfall regions are naturally acidic. Samples from these districts typically indicate a pH between 4.0 and 6.5. Drier inland plains and semi-arid zones are more likely to have neutral or alkaline soils with pH readings between 7.0 and 8.5.

Vegetables, fruit and most other plants prefer to grow in soils with a pH range between 5.5 and 7.5. There are some exceptions, and a number of common species like sweet pea and gladioli prefer more alkaline soils. In general, the symptoms of excessively high or low pH include yellowing leaves, lack of flowering, retarded growth and, in some instances, death of the plant. The health of beneficial micro-organisms and availability of essential plant nutrients are both influenced by the pH characteristics of the soil. When a soil is too acidic or alkaline, plant nutrients become insoluble and cannot be absorbed at the roots. Under such extremes of pH, the soil bacteria required for plant growth are unable to multiply in sufficient concentrations and may in fact be replaced by organisms which release toxic elements.

When assessing soil pH, it is once again important to obtain a representative sample. This generally requires an average of several independent measurements and the discretion to avoid inaccuracies arising from sites where the soil pH has been influenced by specific garden applications. These include samples taken from recently fertilised beds, around woodpiles, compost heaps, incinerators or distinctly burnt areas.

Growing in containers provides a great deal of flexibility and solves problems that might otherwise limit the creativity and enjoyment of organic gardening. Containers provide the essential platform in garden locations without soil such as patios, paved courtyards, and roof areas. They may offer the only means of gardening for individuals living in flats or apartments with limited space. Many urban dwellers have enriched their lives by growing collections of herbs in pots and containers on a windowsill. Most importantly, containers can sustain a range of plants that will struggle or fail in local soil and conditions. For example, in climates where the winter would normally kill a lime or tangelo, these can be grown successfully in containers, so long as they are carefully located in a sunny position and protected against extremes of cold and frost.

A collection of containers is capable of exhibiting a diverse range of plants and enables them to be creatively arranged according to mood or situation. Plants can be relocated to take advantage of contrasting colour, height, and shape. Those with the healthiest foliage or that have commenced flowering can be moved to a more prominent location. The possibilities are almost infinite.

Pots and containers

Pots and containers come in a wide range of size, style, and quality. Traditional stone and terracotta pots grow more beautiful with the patina of weathering and their earthy tones provide the perfect complement to subtle shades of flower and foliage. They are not as common or popular with gardeners today but can still be purchased from artisan manufacturers in most larger cities. One of the slight drawbacks with terracotta is its porous permeability. Plants growing in terracotta vessels will generally require more frequent watering than those in glazed ceramic, plastic or metal containers.

Good quality glazed ceramic containers tend to be heavy, expensive, and not as widely available as they were several decades ago. They can occasionally be grabbed for bargain prices at garage sales and opportunity shops. For serious gardeners, it is well worth investing the money or time to secure these. Properly cared for, they will last and with their beautiful shapes and brilliant glazes will add to the overall vitality of a container garden.

Plastic containers are cheap, light, easy to obtain and come in a spectrum of shapes, colors and styles. Despite their many advantages they lack the character and substance of ceramics. For some individuals, a garden dominated by disposable plastic containers might even conflict with the underlying philosophy of an organic approach. Metallic containers include those made from copper, brass, aluminium and stainless steel. They are often painted however the raw metal can look attractive in some settings particularly where the surfaces have been allowed to weather and mature naturally.

Recycled objects

Another option for the container gardener is to make use of recycled objects. This invites a creative approach, since a seemingly random collection will eventually suggest its own unique sense of individuality, humour or theatre. Old boots, buckets, a watering can, a hollow tree stump, toilet bowls, a spare tyre, even a bathtub are all possibilities to be entertained and there are certainly always more be discovered.

Whatever the choice of container for planting, there are several important characteristics which should be standard. The size of a container will determine the type of plants that can be grown. Shallow rooted varieties like lettuce or chives will manage adequately in smaller pots with a depth of around twenty centimetres. Most varieties with longer roots will require larger and deeper vessels. All plant containers require holes in their base to facilitate drainage. It is standard practice to place a shallow layer of gravel over the base of containers before filling them with potting mix. This ensures an adequate drainage that prevents the mix becoming waterlogged and subsequently drowning the roots.

Watering

Determining the appropriate frequency and volume of watering is one of the most important and challenging aspects of container gardening. In warm, dry conditions, potted plants generally require an automatic watering system or fairly constant attention. In cooler weather, the main risk is over watering and eventually drowning the roots. Sometimes the surface of the potting mix will look and feel dry but it is important to dig a few centimetres below this base. When a sample of mixture taken from this depth feels slightly moist and springs back when pinched between the fingers, there is no need for additional watering. Obviously, the ideal situation is to maintain this level by replacing water at the same rate it is drained, evaporated and taken up by the roots. This is where an automatic watering system or patience is required.

Potting mix

Plants housed in containers require an organic potting mixture since they will not usually obtain enough nutrients from ordinary garden soil. In addition to plant nutrients, organic mixtures provide water and air for the roots. Like sponges, good quality mixtures are structurally designed to hold a separated dispersion of air and water particles. When saturated by over watering, the mixture tends to break down, air particles get displaced, nutrients are washed away, and the overall structure is weakened. While most commercial varieties tend to be excellent and convenient products, it is certainly possible to make organic potting mix at home using combinations of natural materials such as loam, garden and worm composts, leaf mould and seaweed extracts. The exact recipe for each mix will vary with the type of plants and their particular climate and growing conditions.

Location

Most potted plants will benefit from a location that receives plenty of sunlight and a good circulation of fresh air. During the peak of summer, try to secure some shade relief for sensitive plants. Particularly in the tropics and sub-tropical regions try to be alert for any weather forecasts of severe rain, hail, or wind. In these situations, smaller containers can be carried indoors, while any that are too large or heavy need to be secured and protected as much as possible.

For absolute beginners or those without the space for a proper garden, containers can be stacked on a balcony or windowsill to provide a small but exciting range of fresh produce. The best plants to grow are smaller varieties with leaves or fruit that can be picked for salads. Herbs like thyme, basil, chives, and garlic are a great choice. Simple salad preferences might be lettuce, cherry tomatoes, peppers, and courgettes. For a slightly more exotic taste go for combinations like endive, mustard cress, chicory, sorrel, and coriander. Remember that most varieties of lavender are beautiful, strongly scented, and an ideal companion plant for edible herbs. Lavender is easy to grow and attracts beneficial insects while helping to repel pests like aphid and mite. Ornamental fruit trees do particularly well in medium to larger size containers. Citrus fruits require lots of warm sunlight but pears and apples will be fine in most cooler climates.

The best medium for growing healthy plants is a rich, loose, and fertile soil. Earthworms make a significant contribution by loosening the soil and providing plant nutrients in their droppings. When they burrow, worms aerate the soil to provide essential oxygen for bacteria, fungi, and other micro-organisms required for soil fertility.

An earthworm can digest approximately half its own bodyweight of soil each day. Given that average populations number hundreds of worms per square metre, the combined effect will be the processing and movement of large volumes of earth each year.

Earthworms concentrate essential nutrients and minerals from soil as it passes through their digestive tract. Their expelled waste, also known as cast, contains many times the nitrogen, phosphorus, and potassium that is normally available from soil.  Additionally, these casts will contain higher concentrations of minor elements such as calcium, magnesium, and zinc. All of these nutrients and minerals are provided in a form that is readily available to plants, a fact that has led to their widely recognised status as a complete and effective plant food.

Encouraging earthworms

One way to encourage a supply of worm cast for the garden is to purchase live earthworms from an organic worm farm or garden centre. They are expensive so it is worth investigating to ensure the purchased species is compatible with the soil and conditions of their release location. To properly establish themselves in a garden, most varieties of earthworm require a loose, moist soil, one that also contains a reasonable supply of organic material. Another option is to raise a colony of Brandling (Eisenia foetida) worms at home. These are not earthworms but a separate species that normally breed amongst loose and decaying plant material. When raised properly in colonies, Brandling worms are efficient and capable of converting small quantities of organic waste into high nutrient cast.

Colonies of Brandling worms can be raised in manufactured worm bins or homes prepared from spare crates, boxes, aquarium tanks, or bathtubs. Any container used to house worms should provide a depth of at least thirty centimetres and have some drainage capacity at the bottom. When properly attended, worm colonies don’t smell and can be safely located in most sun sheltered spots with a reasonably stable temperature.

A new worm colony will require a minimum of one hundred worms to function properly. If more can be obtained, the colony can establish itself sooner and will be less likely to fail. Until they are making their own compost, a quantity of bedding material will be required to house and support the worms. Suitable materials include manure, compost, or leafmould. Fibrous material such as shredded paper, cardboard, or hessian can also be included.

Feeding earthworms

It is beneficial to feed worms a varied diet of vegetable and garden scraps, including tea leaves, crushed eggshell, and dried fish bones. Overfeeding is a common mistake, particularly for newly housed worms in the process of establishing themselves. Brandling worms are very effective at breaking down organic matter but they are small organisms and their digestive systems can only process limited quantities at a time. If the worms are given more food than they can digest, the unused material will putrefy, making the compost acidic and foul smelling. When allowed to continue, such an environment becomes unsuitable for the worms and they will eventually die. Until their feeding capacity is properly understood, it is safer to restrict the supply of food each day.

After several months the worm farm will contain a supply of rich compost. A portion of this can be removed at any time by digging below the surface with a trowel. The compost can then be applied directly to garden beds and potted plants along with any liquid manure collected from the lower drain. Whenever worms need to be separated from their compost, the best approach is to spread the mixture thinly, outdoors on a sheet of plastic. A sheet of wet cardboard can then be folded over this as a canopy for the worms. Because they prefer to avoid heat, dryness and light, most of the worms will take refuge beneath the canopy and can then be collected as a wriggling mass.

Over the years, I’ve experienced only minor problems associated with inadequate soil drainage. This surprises several of my gardening colleagues since I have frequently worked in regions where rainfall exceeds evaporation and contributes to an elevated groundwater. In retrospect, I was fortunate to work on private estates where adequate garden drainage was designed and installed, sometimes dating back to Elizabethan times. Of course, natural determinants of poor soil drainage can be sufficiently inherent to defy normal engineering attempts to resolve them.

Soil drainage properties can usually be explained in terms of the geographical location, surrounding physical topography, and the compositional structure defined within the various soil layers. For a physical scientist, drainage is evaluated with minimal reference to the effects on a soil’s fertility and its capacity to nurture healthy plant growth. Gardeners will appreciate that a vegetable like the potato can only be planted in soils with optimum drainage and aeration characteristics. Alternatively, there are well known species like the cranberry which succeed admirably in heavy, waterlogged conditions. As much as possible, I try to match individual plant species according to the aeration and drainage characteristics of specific garden locations. To assist me in this, I often depend on nothing more than general observation and some simple field testing.

Why aeration and drainage are important?

Good soil aeration is important for many garden plants. At the structural level, it is dependent upon the amount of pore space existing between the soil particles. There is also an effect determined by the physical composition of these particles, particularly their ability to form aggregates. Otherwise described as clods, the physical cementing of smaller particles provides a mechanical strength which enables pockets of air to be maintained within a soil despite heavy watering from above or the gradual rising of groundwaters from below. When reliable drainage is hampered, air pockets surrounding soil particles are replaced by water. This waterlogging restricts the availability of gaseous oxygen which is essential for healthy soil organisms and normal root development.

As the available oxygen decreases, the normal concentration of carbon dioxide may increase to a level which is toxic for many plants. Carbon dioxide is produced by living organisms and usually comprises around one percent of the gaseous substances held within soil. While carbon dioxide concentrations for well aerated soils are approximately ten times the normal atmospheric level, poorly aerated and waterlogged soils will exceed this by multiples. The extreme effects of restricted aeration and drainage can be observed in a peat bog. These will generally be colonised by bacteria capable of surviving with minimal oxygen. Because they possess limited abilities to decompose plant materials, extremely waterlogged soils tend to contain high quantities of unprocessed organic material. This problem is often due to poor soil structure combined with an exposed or depressed location that collects rainfall and condensation.

Checking your soil

When doubtful about a particular section of garden, I use a simple procedure to test the soil for adequate drainage. The first step is to dig a series of thirty centimetre deep holes approximately one metre apart. These holes are deliberately filled with water from the hose. The next step is to evaluate the amount of time required for each of the water filled holes to drain completely. Provided the water drains completely within several hours, the soil will suit the majority of garden plants. Should some of the holes still contain water after this period, the possibility of a significant drainage problem must be considered.

As mentioned earlier, most of the drainage issues from my own gardening experience have been relatively minor and were able to be solved with simple remedies. In the past, for example, I have treated damp clay soils with a mixture of gypsum and coarse river sand to improve their drainage characteristics. Gypsum provides a soil with the abundance of calcium ions which subsequently lowers the concentration of sodium. Apparently, it is high levels of soluble sodium which disperses additional clay particles and therefore contributes to the poor drainage observed in these difficult soils.

Occasionally, it will be helpful to undertake some structural solutions to a mild but persistent drainage issue. Structural solutions are suitable for small problematic sections of the garden, particularly when these would otherwise disrupt the natural flow and harmony of design. Raised garden beds are easy to manage and provide an effective remedy for inadequate drainage. A structural barrier is built to contain a growing medium which is rich in organic materials, and of a texture that supports a healthy mixture of air and water around soil particles. A base of gravel will enable excess moisture to be released from the bed, protecting soil and plants from the risk of becoming waterlogged. These are not always easy to build as some might claim. I usually advise novice gardeners to seek qualified assistance when designing and constructing their first elevated garden bed.

When it’s serious

Serious drainage problems can be difficult and expensive to correct. It is often expedient to consider practical steps and solutions before installing plumbing or undertaking structural improvements to land or property. Some soils drain poorly due to surface compaction and will benefit from a digging over with the incorporation of organic matter. If this fails initially, the top metre of soil can be removed in small sections to enable a ten centimetre layer of coarse gravel to be laid as a supporting foundation. The soil is then mixed with additional organic materials and carefully replaced.

Land drains can be installed to channel water away from sections of the garden. They may provide the best practical solution in regions with an elevated water table or those prone to periodic flooding. They are also appropriate whenever water threatens housing or the safe use of an area. Often requiring high levels of technical expertise, land drains should be designed with input from qualified landscape consultants, even a hydrologist in the case of serious drainage problems.

It saddens me to admit that the prevalence of seriously problematic soils appears to have increased dramatically over the previous few decades. Despite the proximity of international tensions, the world seemed a considerably safer and altogether more stable environment when I started gardening in my teens and early twenties. Perhaps this misrepresents the reality. It might be more accurate to suggest that certain issues were once described in concrete terms, without the numerous complexities and differences of opinion which are routinely encountered in the popular media of today. Like everyone else, I’m confused and disturbed by the reports on global warming, climate change, and species decline. When I look at my original notes for this section, I’m aware that I intended to separate problem soils into two distinct categories. Problem soils determined by geographic and environmental factors versus those which are distinctly caused by situations of adverse human influence. If it is true that we have irreversibly upset the stability of our global weather patterns, my attempt to differentiate these two categories should perhaps be revised.

Environmental factors

In most cases, problem soils will be characterised by the influence of extreme geographic or climatic conditions. They may also be contributed to by human impacts such as structural erosion, overly intensive agricultural practices, and industrial contamination. Newly released land developments are often criticised for their soils which seem incapable of supporting a garden. Modern subdivisions may include unstable tracts of wetland and those which have been inappropriately reclaimed using cheap and readily accessible fill materials. As modern urban regions expand toward and beyond their planned boundaries, another relatively common practice involves the rezoning of previously agricultural and industrial land into residential allotments.

Reclaimed land

The soils of reclaimed agricultural lands may suffer from a range of problems such as erosion, salinity, severe nutrient deficiencies, and toxicity related to agricultural chemicals and other treatments. Depending on its previous use, reclaimed industrial land may contain soils contaminated with unacceptable levels of toxic metals, hydrocarbons like diesel oil, and chemical substances which remain potentially harmful for many years. Such irresponsible land practices can result in entire neighbourhoods without gardens. Several years ago I happened to visit one of these reclaimed suburbs and was astonished to learn of the thriving local trade in plastic and artificial plants. I was driving on a wide road with a pink sunset behind me. Everything seemed surreal and unfamiliar. I tried to imagine what it would be like for the parents who built plastic gardens for their children to play in. 

Local knowledge is invaluable

The likelihood of correcting specific soil problems is greatly increased by gathering sufficient knowledge concerning local geography and the human interventions which might have disrupted the site’s natural composition and structure. Many suburban soils, for example, are seriously degraded by the erosive influence of their climates. This is particularly apparent in regions where a hot, dry season alternates with one of high rainfall.

Accelerated erosion can also occur on alluvial plains supported by river systems which are diverted for cropping irrigation. Over time, the slow drying of river tributaries can severely reduce trees, native grasses and groundcover, leaving the uppermost layers of humus exposed. The topsoil is then vulnerable to being blown or washed away, leaving subsoil deficient in organic material and plant nutrients. Because the subsoil remains permeable to subterranean water, mineral salts may be deposited in quantities sufficient to cause further destruction to soil organisms and plants. In many cases of erosion, the short-term remedy involves incorporating organic material and securing the remaining nutrients with a suitable groundcover. Hardy native grasses and low growing shrubs with complex root systems are often ideal for this purpose.

Chemical and industrial contamination

In my opinion, it is imperative to obtain professional advice in those cases where a garden or property is likely to be affected by chemical or industrial agents. Given the current rate of land reclamation within major cities, it would be helpful for prospective purchasers to include soil analysis as a component of their property inspection and valuation reports. In the United States alone, there are numerous litigations involving the sale of contaminated residential properties. The problem may widen considerably as industrially exposed land is increasingly exchanged and developed within economically emerging nations like China, India, and Vietnam.

The effective treatment of seriously contaminated soils can be extremely expensive and time consuming. When the contamination is restricted within a manageable surface area the usual treatment is a combination of soil replacement and the application of activated charcoal. This can be purchased from organic garden centres and should be spread over affected areas in quantities specific to the manufacturer’s recommendation. Over time, the charcoal will neutralise and absorb a wide spectrum of chemical residues. As a bonus, any excess charcoal will provide useful minerals and plant nutrients while improving soil drainage.

The decision to use a particular type of fertiliser needs to be supported by some understanding of the preferred soil conditions and other requirements of the plants being raised. To grow properly, plants require a broad selection of nutrients. Ideally, these occur naturally and are directly available from soil or compost. The three macro or major nutrients: Nitrogen (N), Phosphorus (P), and Potassium (K), are required in significant quantities. They work together and in combination with other nutrients but each of them has a dominant role in certain aspects of growth and plant development. Nitrogen, for example, is required for shoot and leaf growth. Phosphorus is the most crucial nutrient for developing functional root systems, while the main role of potassium is supporting fruit and flower formation. Around a dozen additional elements are required in relatively small quantities. These include Calcium, Magnesium, Sulphur, Zinc, Iron, and Selenium; also know as the trace or minor nutrients. They make significant contributions to overall growth and development, and seem to be particularly important for building general immunity and resistance against disease.

Each species of plant has an optimal requirement for quantity and balance of the essential nutrients. When plants fail due to a specific nutrient deficiency, it can be challenging to first identify then correct the problem. When affected, most plants will exhibit some general symptoms like stunted or deformed growth, leaf discolouration, mottling, and root shrinkage. Often, these signs first become apparent at the outer branches and leaf tips since these are furthest from the source of nutrients. In some instances, a soil will contain nutrients that are locked and unavailable to the plant. Excessively high concentrations of certain elements can create toxic effects or block the availability of other essential nutrients. They are both risks that should be considered prior to soil treatments, particularly those based upon a synthetic chemical product.

Chemical fertilizers

Synthetic chemical fertilizers are water soluble and capable of releasing their nutrients quickly. They are usually manufactured from mineral salts like nitrates of potassium, calcium, and ammonium. High concentrations of these are not good for plants in the long term and their effects have been compared to those of highly refined sugar in human physiology. To improve the appeal of their products, most manufacturers of synthetic fertilizer have developed coatings that enable them to break down at a much slower rate and release correspondingly smaller quantities of water soluble nutrient at a time. While this represents some improvement, it cannot prevent the problems and wastage associated with their eventual leaching from soils into rivers, drains and reservoirs. The repeated use of fertiliser also neglects the basic principle of assisting plants by improving their soil conditions.

During their manufacture, the concentration and quantity of various compounds within synthetic fertilizers can be precisely controlled according to standard formulae. This enables the products to be expressed as a series of three numbers. The first is the percentage by weight of nitrogen, followed by phosphorus then potassium. In addition, the percentages of each contributing trace element can be clearly defined. By contrast, constituent compounds in natural organic fertilizers can only be estimated and will vary according to the ingredients used for each batch.

An organic approach

Within the organics movement, fertilizers are generally afforded a minor role compared to soil conditioners. Traditionally, the emphasis has been placed upon building the soils capacity to deliver nutrients rather than feeding these directly as supplements to plants. When organic fertilizers are required, they are made from natural materials such as bone meal, fish, seaweed, nettle, comfrey, and other plant extracts. Strategic applications of organic fertilizer can provide nutrients and trace elements that are absent from a soil. They are released slowly to plants because they contain compounds that need to be broken down by soil bacteria. This process can be accelerated under warm, humid conditions or retarded in cold and dry.

Liquid preparations of organic fertilizer are easy to use, readily absorbed by most plants and less likely to alter soil chemistry than granular fertilizers. It is quite easy and rewarding to make liquid fertiliser at home using organic materials. Nettle leaf extract is a good general fertilizer which contains a balance of macro nutrients and trace elements. Nettles can be collected in spring then placed inside a hessian sack that is loosely tied then suspended in a large bucket containing approximately ten litres of water for each kilogram of leaves. After one month the liquid should be strained, diluted with five parts water then bottled in suitable containers. Liquid fertiliser can also be made from comfrey, kelp, clover, and other crops used for green manure.

The other night, I became frustrated with my football coverage so switched between documentary channels on the cable network. I managed to catch the second half of a program about earthworms. Prior to final credits, the narrator emphasized the significance of the earthworm’s contribution towards maintaining soil fertility. He then suggested that soil fertility was crucial for the long term sustainability of life on earth. Unfortunately, he repeated the words monotonically and they became divorced from any reasonable sense of urgency.

As a keen student of organic principles, I’ve been concerned about the long term consequences of poor quality soils for several decades. Irrespective of the demand for organically grown produce, there are large numbers of consumers who remain misinformed about the importance of soil quality in determining the nutrient values of their basic foods. While vegetables raised in deficient soils may appear and taste adequate, they will not necessarily provide the complex balance of nutrients required for optimum health. For those interested in raising organic vegetables, a basic understanding of factors influencing soil fertility will provide the most reliable foundation for positive results.

Soil degradation

What are the underlying causes of soil degradation and infertility? In terms of natural environments, erosive actions caused by wind, sun, water, and seismic disruptions are all potential contributors to soil degradation.

How do erosive forces influence soil fertility? Physical and chemical changes can disrupt the soil’s living organisms and their capacity to perform certain beneficial functions. This may occur as a consequence of habitat destruction or the depletion of important resources. The evidence of habitat destruction may be concealed.  Consider the example of a subtle surface compression restricting a soil’s ability to deliver water and oxygen.

On other occasions, habitat destruction is externally obvious. For example, large quantities of topsoil might be stripped from one location. While external signs of physical erosion can be observed in many regions, they tend to develop over extended periods and appear more obvious in extreme climate situations like those experienced in desert, tundra, and alpine locations. 

Soil degradation is also caused by a broad range of human activities including intensive agriculture and the appropriation of marginal and fragile environments for cropping and food production. During the latter half of the previous century, the steady accumulation of political and technological influences coerced significant numbers of food producers to adopt an intensive approach to agriculture. Instead of focusing on the complex determinants of natural soil fertility, intensive agricultural production depends on chemical assistance to regulate plant growth.

Water soluble fertilizers feed plants directly, bypassing the complex nutrient cycles which plants have traditionally depended on to remain healthy. The widespread use of synthetic chemicals is associated with a marked decline in the quantity and diversity of soil organisms. Consequently, many of these chemicals decrease natural soil fertility and plant health. The symptoms are frequently observed in private gardens, including those devoted to vegetable production.

Ecosystems and soil fertility

Optimum soil fertility depends on establishing ecosystems which facilitate the efficient recycling of nutrients. Ideally, soil nutrients are absorbed by living plants and animals which must eventually restore the balance of organic materials by means of excretion and physical decomposition. Under such conditions, healthy plants will develop beneficial relationships with soil bacteria and other organisms. An example of this are rhizobial organisms which attach themselves to the roots of legumes. While feeding on root secretions, they release compounds which enable the plant to obtain and absorb nitrogen from the atmosphere. Similarly, there are fungal organisms which penetrate plant roots and enable important soil nutrients to be transferred directly into the root system. Growers resorting to chemical fungicides and other treatments inevitably shift the balance between these organisms and risk losing their positive functions.

A powerful magnification of soil samples from an organic garden should typically reveal a complex diversity and abundance of microbial organisms. The majority of these organisms contribute to their ecosystem by breaking complex organic materials into simpler components which release energy and facilitate the storage of soil nutrients. Several classes of organism influence soil fertility by improving the structural composition of soil particles. They excrete various substances which function as an important cement between soil particles. Ideally, this enables soil particles to be combined in matrix arrangements which provide adequate surrounding spaces for the distribution of water and air.

When attempting to raise vegetables organically, it’s important to appreciate soil as a dynamic ecosystem with broader capabilities than a simplified growth medium for plants. In order to sustain fertility, the soil ecosystem requires continuous energy which is supplied by the combination of sunlight and the decomposition and eventual recycling of complex organic materials. There are three broad phases in the decomposition of organic materials which, in most gardening situations, will directly influence a soil’s fertility. The first of these relates to the availability of partially decomposed organic substances. The second relates to substances which have been recombined into new compounds following an advanced stage of decomposition. The final category is used to describe high molecular weight compounds which have been fully decomposed and stabilized against further decomposition. To remain viable over the longer term, these phases of decomposition must occur naturally within the soil.

A majority of cultivated vegetables have high nutrient demands which must be provided within relatively short growth periods. To what extent can these short term demands be sustained by pursuing the organic principle of routine soil replenishment? The best answer begins with a further question. How efficiently can organic materials be converted into the basic nutrients which are then absorbed by plant roots? This primarily depends upon the availability of energy. Throughout the active phases of organic decomposition, the speed of nutrient release is partly determined by localized temperatures within surface layers of soil. Warm soils are generally required to promote rapid decomposition and nutrient recycling. A soil’s warmth is generated from sunlight and the biological processes of numerous living organisms.

Soil chemistry and structure

The efficiency of nutrient release is also influenced by aspects of soil chemistry. Living vegetables have the capacity to absorb nutrients in the form of ionic compounds. While organic material represents the ideal collection point for many of these electrically charged compounds, a nutrient deficiency or imbalance can be worsened by the indiscriminate application of unsuitable organic materials. If a soil becomes severely deficient in calcium and magnesium, for example, the addition of potassium rich compost or fertilizers will generally slow the release of deficient minerals and further distort the soil’s profile. When a sustained application of organic principles fails to provide positive results, a professional soil analysis is a worthwhile investment.  

After several seasons of organic vegetable production, most gardens will benefit from a fallow period and the addition of soil conditioners to replenish those nutrients depleted through repeated cycles of plant growth. Naturally sandy soils will benefit from the addition of moisture holding materials. Depending on what is readily available and cost efficient, choose organic cow or horse manures, peat moss, spent mushroom or garden compost. Heavy clay soils are best improved with mixtures of dry organic material such as seaweed, leaf mould, shredded straw, sawdust, wood shavings, and worm casts. Such dry materials build soil structure by loosening and separating some of the tightly bound clay particles. Subsequent additions of coarse grade river sand will reinforce this process. 

When the vegetable garden is maintained with generous amounts of organic material, most plants will grow superbly without requiring additional fertilizer or nutritional supplementation. There are however, some occasions when high quality organic plant supplements can be useful. Vegetables sown a week or two late in the season can be encouraged to catch up with an extra dose of nitrogen rich fertilizer. This promotes rapid leaf growth, and is particularly useful for salad greens, lettuce, and spinach. Potassium based organic supplements are designed to encourage flowering and fruiting so may apply to certain varieties of zucchini, eggplant, and cucumber for example. I used to make my own plant foods in the form of liquid extracts but am currently sourcing a granulated mix from some local plant breeders who combine large quantities of natural organic ingredients to create well balanced garden fertilizers. Their standard mix contains equal amounts of linseed meal, kelpmeal, and guano. Their key ingredient is the kelpmeal. It costs several times more than the others but contains the natural hormones and growth regulators which assist vulnerable plants and seedlings to resist stresses like sudden cold spells and mild dehydration  

Commercial products which claim to increase the size and yield of garden vegetables should be evaluated cautiously. The treated vegetables may be large in size but bland of flavor due to their higher than usual cellulose and water contents.

In their uncultivated state, plants must continually depend on their adaptability for survival. In addition to accommodating local variations in their environment, they need to compete against rival plants for their share of soil nutrients and other resources like water, sunlight, and physical space. While this competition can frequently be harsh and unforgiving, there are also situations where plants benefit from establishing mutually co-operative relationships with non related species. By closely observing nature over many years, I have learnt to appreciate and accept these complex patterns of ecological rivalry and cooperation. In turn, this provides me with a useful foundation for establishing companion planting programs within my own organic garden.

A process of discovery

To organic beginners, the concepts of companion planting may well appear inconsistent and shrouded in obscurity. I still recall examining the topic and becoming entirely frustrated by its lack of unity and scientific explanation. That was nearly fifty years ago. In the meantime I’ve mellowed considerably and am now prepared to exchange solid explanations for the flexibility of approximation and practical efficiency. I no longer feel pressured to understand the technical aspects of every situation. When a companion planting strategy works, my current approach is to relax and enjoy the success. Often there’s a scientific or technical rationale which becomes evident at a later date. I might discover this purposefully or by accident: through any combination of fortunate observation, applied research, casual reading, or conversations with other gardening enthusiasts. That’s the excitement of discovery. It can be wonderful, and deeply satisfying on occasions. Alternatively, I’m left unable to explain why a particular planting has succeeded or failed, either to myself or my friends and associates. That’s okay too. Perhaps I will figure it out sometime later.

Here are some examples of companion plantings which have succeeded in my own gardens on various occasions throughout my career. I’ll begin with plantings which can be rationalised to an extent then conclude with those which work for unknown reasons.

Combinations which promote an efficient distribution of resources

There are numerous planting combinations based upon the efficient distribution and utilisation of garden resources. It’s lovely to reap the rewards which arise from devising combinations which facilitate a mutual cooperation between distinct plant species.

The umbrella arrangement involves interspersing tall or climbing plants with several rows of shorter plants which can benefit from the physical protection and partial shade. One of my favourite examples is to plant several rows of English spinach between broadbean or sweetpea. In exposed areas, spinach requires substantial protection from drying winds and harsh sunlight. I particularly recommend this planting to warm climate gardeners who might have become frustrated by the tendency of English spinach to run to seed before harvesting.  

The most popular plantings within this category involve the positioning of shallow rooted species alongside those with deeper root systems. This enables water and nutrients to be shared while soil structure is improved by  the root foraging which occurs at separate levels. There are numerous examples which can be widely applied although their ultimate success depends upon local climate and soil conditions. Beginners might attempt a small plot combining lettuce with carrots or beetroot while experienced growers can often accommodate larger fields with productive combinations like potatoes and cabbage, or turnips with nasturtium.

Heavy feeders like sweetcorn and squashes are frequently planted alongside nitrogen fixing legumes such as beans or peas. This offers substantial protection to a soil’s nutrient profile, particularly its ongoing ability to break down and absorb organic soil additives such as dried manure, seaweed, and peastraw.

Combinations to discourage and control garden pests

A disadvantage of growing one species on a large scale (monoculture) is the devastation caused by sudden infestations of plant destroying insect. One theory suggests that monocultures produce concentrated biological signals, thereby attracting pests in significantly greater numbers, and from beyond their normal range. The introduction of carefully selected companion species weakens the attraction signals and discourages the arrival of many destructive insect species.

When cabbages, broccoli and related plants are interspersed with rows of onion, they are less prone to caterpillar and other larval infestation. This is principally due to the onion’s stronger scent and its capacity to confuse or deter cabbage moths.

Various culinary and medicinal herbs have gained reputations for their insect repellent properties. The complex aromatic oils of garlic, cloves, basil, lavender and sage will discourage aphid, fruitfly and other insects from attacking vulnerable species like citrus, rose, lettuce, and stonefruit. When planted in close proximity to seeding beds, tansy is an effective deterrent against cutworm, cabbage worms, and many types of caterpillar.

Astute organic growers frequently plant companion species to discourage pests from eating their primary crops. Redcurrants are used as a sacrificial plant to distract birds and other species which otherwise feed upon strawberries, raspberries, and blackcurrants.

Traditional planting combinations

There are traditional planting combinations which seem to work yet cannot be explained in any conventional sense. Chamomile (chamaemelum nobile) is frequently grown alongside culinary herbs where it has the effect of encouraging increased production of their essential oils and flavour characteristics. I first experienced this phenomenon on a friend’s property located near the Welsh border. He specialises in aromatic herbs like oregano, sage, and thyme. After lunch, we were invited to compare the difference between his plants raised alongside chamomile and those gathered from separate fields with a mixture of native grasses and bracken fern. I was astounded by the difference and found myself planting chamomile throughout my own herb gardens. Personal experience with this planting suggests an effective advantage which is restricted to the coarser Mediterranean and African varieties. There appears to be minimal improvement with the English, French, and Asian herbs.

Despite the conservative nature of their industry, viticulturalists are well known for the obscurity of their companion planting practices. My favourite example is the decision to grow ornamental basil between established and old growth vines. I have observed this practice on an exclusive Bordeaux vineyard renowned for the superior quality of its Grenache and burgundy varietals. In Argentina and parts of rural Spain, high quality organic grapes are occasionally interspersed between wild geranium bushes and mulberry trees. Ripening mulberries appear to attract local birds preventing them from interfering with the grapes. There is however more to these pairings than that which can be immediately appreciated by an outsider with limited conversational Spanish. I’m always fascinated by the fact that immature vines are abandoned season after season, until some combination of factors make them appealing and acceptable to the seasoned expert.

Experienced gardeners will commit themselves to few rules and even fewer certainties with companion planting. Most of us need to experiment with several approaches and will usually discover that success depends upon location, soil condition, and other factors in addition to the combinations themselves. Bearing this in mind, it is good practice to keep detailed records of each attempt so that similar conditions can be repeated whenever a successful outcome is achieved.

In recent years, there has been a considerable shift away from the chemical approach to insect control. This is often explained in terms of the increasing cost of developing new formulations to combat elevated levels of resistance within several insect populations. At the same time, the accessibility of international travel combined with progressive reductions in agricultural trade restrictions have contributed to the increased risk of introducing previously unfamiliar insect species to working farms, and gardens throughout the country. In their efforts to control troublesome insect populations, organic gardeners and primary producers depend upon a restricted range of natural products and control strategies. These can be grouped within four broad categories.

Bolstering plant resistance

The first of these include all of the efforts which seek to improve the plant’s biological resistance and resilience against insect attack. This is generally achieved by encouraging natural soil fertility and promoting a diversified ecosystem. The positive relationships between healthy soils and healthy plants provide an underlying framework for the organic approach to insect management. It is reasonable to assume that the organic emphasis on soil quality will result in improved nutrient dynamics which subsequently enable the plant to resist many forms of insect attack. The lower incidence of pest infestation on organic farms and gardens is also attributed to the biological diversity which encourages natural insect predators and resource competitors. It is important to avoid the situation where one plant species predominates over a large section of the garden. This encourages insects to establish resident populations.

Physical deterrence

The second category of insect control measures is based upon physical deterrence. In many situations, it is appropriate to remove problem insects from the garden. Destructive invaders like snails, slugs, and caterpillars can be physically removed from plants and collected in plastic buckets containing methylated spirits or saline solution. There are plenty of screens, traps, water sprays, and other devices suitable for the organic garden. Commercial insect screens and finely meshed gauze nets can be used as protective barriers against medium and larger sized insects such as fruit fly, locust, and caterpillars. When properly secured, the screens also prevent access to birds and rodents. The negative consequence of widespread insect screening can be the restriction placed on useful pollinators like bees and honeyeaters.

Many types of trap are used to capture insects. Fruit flies can be captured in plastic bottles or closed funnels containing baits which mimic the signals of sexual attraction. Slugs and snails will drown in plastic basins containing several centimetres of beer at the bottom. Traps like these can help to control insect numbers but may also be used to monitor seasonal variations in the population. This information can be used to establish crop rotations which strategically disrupt breeding and activity cycles. Sprays of water are suitable for physically washing mites, aphid, and other minute insects from foliage. Electronic or mechanical timers which initiate periodic jets will restrict most of their opportunistic movement and behaviours. Most garden centres stock a range patented devices, some of which are designed with the organic gardener in mind. Good examples are the copper strips which can be used to control slugs and snails in most suburban gardens. Individuals who loathe shopping may prefer to depend on the old fashioned remedies. One of my favourites is the use of crushed eggshell or finely ground bone fragments to protect seedlings from slugs and snails.

Natural predators

Natural insect predators provide another type of control measure. There are numerous predatory organisms which can significantly limit the destructive effects of plant feeding insects. It is possible to encourage beneficial predators into a garden but, ironically, this requires viable populations of the pest species to sustain and hold them. From an ecological perspective, the aim is to establish an acceptable equilibrium between these two populations, rather than attempting to eradicate one of them.

Typical examples of beneficial predators include birds, lizards, spiders and a host of carnivorous and parasitic insects: ladybird, lacewing, praying mantis, hoverfly, wasp, predatory mite and nematode. The presence of these species suggests that a complex, self-regulating ecosystem is established. To maintain this, a varied range of plant habitat and sheltering zones are required. Birds prefer trees and open areas; lizards seek grassy cover and hollow logs. The predatory insect species usually depend on nectar or fruit bearing plants to attract their prey.

Biological control

Biological control is also dependent upon identifying species which prey or compete against an established insect pest. Unlike natural insect predators, the majority of organisms used as biological control agents are manipulated by some human intervention. This may involve breeding programs in which an introduced species is released in populations of sufficient size to impact upon the nuisance insect. Biological controls in agriculture are frequently established within the field of microbiology. Various microorganisms such as bacteria, fungi, viruses, and protozoa can be manipulated to improve aspects of the organic ecosystem. These interventions will be ecologically sensitive and expensive, so are usually restricted to specialist growers with sufficient resources and government approval. At the lower end of the scale, many organic gardeners are familiar with the microbial based insecticide known as Bt. This product is developed from selected strains of Bacillus thuringienis bacterium, which releases a natural toxin killing many species of caterpillar and other destructive larvae within several days.

In some situations, an insect population may eventually adapt and become resistant against the individual control strategies described here. Experienced organic gardeners will routinely vary their approach, particularly during prolonged breeding cycles and periods of seasonal acclimatisation when normal resistance is diminished. Dependent upon local growing conditions, there may be opportunities to combine several of the outlined strategies for insect control.

It is estimated that a majority of organic gardeners will be challenged by several outbreaks of plant disease during each growing season. This statement never fails to alarm a small percentage of faces in my audience. I quickly identify them as worry prone gardeners. Occasionally, they will approach me following a speaking engagement. Some of them possess an encyclopaedic knowledge of plant disease. They worry and fret over every perceived blemish. Patchy lawns, curled leaves, mottled bark, misshapen flower buds, and so on. After brief discussion, I appreciate their anxieties but cannot genuinely help them. I have also encountered the opposite reaction in gardeners. There are a minority of individuals who refuse to acknowledge serious problems when they occur. Surrounded by obvious and widespread symptoms, they somehow prefer to avoid any of the assertive actions required. While both behaviours can probably be attributed to some form of fear, I would personally prefer my closest neighbours to be the worry prone – as opposed to oblivious – variety of gardener.

While I have certainly chosen to describe two polar extremes of gardening behaviour, we are all capable of unnecessary panic, and neglect on occasions. At the present time, there are no magic bullets, nothing in the manner of a universal remedy which will safeguard our plants and gardens from the threat of disease organisms.

All we depend upon is resourceful intelligence and experience. Disease prevention and control can be simplified to compose four basic objectives.

• Disease risk analysis
• Identification of significant disease symptoms
• Strategies for prevention within an organic framework; and
• Control and treatment measures that can be safely applied within the integrated organic environment.

Let’s consider these in a little more detail.

The analysis of disease risk

Plant and soil borne diseases are classified by the biological status of their active pathogen. The commonest pathogens are the microscopic fungi, bacteria, viruses and nematodes. Most of these pathogens are opportunistic, surviving in small numbers until prevailing conditions enable them to rapidly multiply. Following this stage, it is usually possible to identify visible symptoms although these will vary according to the types of plant affected, the climate, soil condition, and the virulence and progression of the active pathogen. Experienced gardeners will also appreciate that the risk of encountering any particular disease will depend upon a similar combination of factors. In most situations the risk can be approximately determined by a careful assessment of the local and seasonal growing conditions, availability of quarantine protections, and the susceptibility of individual plant species.

For every organic gardening forum I attend, I always expect to learn at least one thing which totally surprises me. Inevitably, the majority of these surprises relate to the peculiarities of a particular geoclimatic situation. I’m constantly telling people there’s no substitute for accurate local knowledge. The most effective gardening strategies are based on specific as opposed to generalist sources of information. This is never more fully demonstrated than the practical aspects of disease risk assessment. Here’s my advice. Purchase a fifty cent notebook and visit your closest public library. Search for publications released by the official departments of agriculture and primary industries. Focus on the most recent reports which describe horticultural diseases and quarantine regulations. While influenced by the local impact of common plant diseases, they also provide some indication of recently introduced strains and those most likely to threaten commercial growers and native species. The next step is to visit local plant nurseries, garden centres, and plant breeders. Ask general questions about local growing conditions. Look carefully at the plants and ask relevant questions. The technical staff will often be trained to provide practical information about the identification of healthy as opposed to symptomatic plants.

If you haven’t already done so, it is time to join the local branch of the organic society. Many participants will be experienced gardeners prepared to share their knowledge on various plant diseases and the level of risk pertaining to these.

Identification of disease

Early detection of plant disease makes it easier to control the spread and thereby limit any negative effects within the garden. The ability to recognise early stages of disease depends upon some understanding of the normal appearance and life cycles of susceptible plants. Excellent information can be sourced from illustrated gardening encyclopaedias and specialist botanical publications. Establishing a routine of physically checking each plants condition is the best way to consolidate and apply the information sourced from books. Early to mid morning and late afternoons provide a softer light, ideal for inspecting foliage, particularly when the magnification of a hand lens is required. Any signs of abnormality should become apparent when compared with that of healthy growth and reproduction.

Prevention strategies 

Plant stress is always a significant risk factor for susceptibility to disease, so avoid overcrowding and preferably choose varieties which are well suited to local conditions. Where individual species are particularly vulnerable to certain diseases, it may be possible to obtain strains developed for their improved resistance. Alternatively, when these are unavailable, it may be wiser to choose plants from a different family. Healthy plants develop their own immunity which provides the best natural defence against most forms of disease. Optimum immunity requires superior genetics, steady growth, and a track history of survival.

It is important to choose and maintain healthy garden sites for the majority of plant species. Damp or stagnant areas can eventually provide refuge for troublesome plant diseases. It is surprising how many disease organisms are destroyed or greatly weakened by sufficient exposure to sunlight and clean circulating air. The lack of sunlight and circulating air appears to contribute to the general susceptibility of many indoor plants.

A soil which is periodically enriched with compost and other organic materials can help plants maintain a steady rate of growth. The excessive use of nitrogen-based fertilisers tends to encourage a sudden proliferation of foliage which may eventually reduce plant vigour and increase susceptibility to disease. Synthetic chemical fertilisers will also deplete the concentration of microorganisms which are essential for breaking complex soil nutrients to a form which can be used by plants. One of the newly emerging garden products are concentrated supplies of these healthy bacteria which can be applied directly to soils to encourage new generations of living organisms. This reflects the organic philosophy of building balanced ecosystems where complex life is intricately connected and ultimately dependent upon the microscopic soil organisms.

When introducing new plants, quarantine them for at least a couple of weeks before planting. To further reduce the risk of introducing disease, all seedlings, mature plants and soil products should be obtained from reputable organic suppliers.

Control and treatment

It is rarely possible to identify a single cause for any disease outbreak. Sudden changes in temperature, rainfall, or soil chemistry can cause microscopic pathogens to be activated from a dormant state. This may precipitate a localised outbreak of disease, but the consequences will vary according to the control and treatment measures applied. The best of these will reduce or eliminate the need to pursue chemical and other potentially harmful remedies.

One of the most effective control measures is to rapidly isolate and contain the originating source of any minor disease outbreak. The isolation of transmissible plant disease requires strict attention to garden hygiene. Many diseases have the potential to spread quickly when infected materials are carelessly handled or disposed. I own several gardening books which recommend deep burial although I generally prefer incinerating diseased and suspect plant materials. Pathogenic fungi spores and bacteria can be carried into healthy sections of garden through the action of wind, browsing animals, and on the footwear or clothing of humans. Wiping garden cutters and other frequently used tools with a sterilising alcohol helps to lower the possibility of transferring disease.

For most gardeners, soil borne diseases are particularly difficult to detect and isolate. Over many years, I had noted that mulched garden beds tended to have significantly fewer incidences of plant disease. It wasn’t until overhearing a comment from an organic strawberry grower that I discovered the likely reason for this. Mulching restricts disease transmission by preventing infectious spores splashing onto plants. It also provides a natural weed control which reduces the need for constant digging and soil disruption.

Until recently, organic certification authorities have allowed commercial producers to use simple fungicidal compounds based on copper, tin, and sulphur. These are effective when administered as powdered or gelatinous agents, controlling a spectrum of fungal disease across diverse plant species including tomatoes, cocoa, potatoes, and grapes. At present, there is a new wave of restrictions coinciding with greater regulation of the various organic industries and the contribution of international trade bodies. This has caused a considerable amount of resentment, particularly among growers attached to the organic wine and beverage industries.

According to my own evaluation of mainstream organic sentiment, there is an approximate division as to whether these substances should be used in horticultural production and general gardening pursuits. From the historical perspective, these preparations appear to have been used with remarkably few adverse effects. One of the arguments for restricting copper compounds is their potential toxicity and the risks associated with ingestion of treated materials. The other concern raised by the organic purists is their possible effects upon soil chemistry and the balance of microbial life forms. Longitudinal testing of vineyard soils in France, Canada, and the United States have, for example, revealed significantly elevated copper concentrations combined with deficiencies of zinc, selenium, and other trace minerals. In view of these findings, I have avoided the use of copper compounds for several years. I occasionally use sulphur dust on my tomatoes but am increasingly shifting toward the use of home made herbal extracts for fungicidal control.

Natural remedies against fungal diseases can be made at home from seaweed and various herbal extracts. I have discovered that infusions of nettle, spring onion, or chamomile are excellent for controlling troublesome mildew on squashes, cucumbers and other climbing vines. To ensure adequate potency, the nettles, spring onions, or chamomile flowers must be carefully harvested from high quality stock. I tend to harvest chamomile early in the spring but keep a reasonable store of the dried flowers for later in the season when fungal problems are on the rise. The flowers or leaves are soaked in boiling water for several minutes. After cooling, the liquid extracts should be diluted to a weak tea consistency. Strain these with a fine muslin filter prior to application. For best results, the strained liquids should be transferred sealed canisters and used within approximately two weeks. In addition to their gentle fungicidal properties, nettle and seaweed foliar sprays provide a range of beneficial plant nutrients.

For those of us living within reasonable distance to the coast, seaweed or kelp can be gathered in abundance after a storm. I know gardeners who fill their trailers several times each year. Unlike many of the chemical fungicides, kelp solutions are entirely safe and simple to prepare. I remove excess salt with a careful rinsing before soaking the long strands inside a plastic basin containing fresh water. After approximately two weeks the concentrated kelp solution should be diluted to the consistency of weak tea. Strain through muslin filters to remove any solid particles then transfer the remaining liquids to a sealed canister. There’s no reason why a kelp solution cannot be stored for several months, although I tend to prefer mixing new batches once the storage period extends beyond a couple of weeks.

There are several botanical and naturally derived substances which can be sprayed in the organic garden to control pests and disease. Widely used before the arrival of chemical products, several of the natural alternatives have become less fashionable and may be difficult to obtain.

I first appreciated the benefits of natural garden sprays several years ago when I helped a close friend whose vegetable gardens became infested with a particularly virulent species of cutworm. Around the peak of spring, she attempted to control them with a well known chemical treatment. Despite repeated applications, the number of cutworm began to increase rather than diminish. By the approach of autumn, her summer vegetables were all but devastated and my friend became reluctant to attempt a winter crop.

When she requested assistance, my initial plan was to work steadily on the soil. By increasing the quantity of organic materials, I hoped to improve the soil’s nutrient distribution and simultaneously encourage the larval predators which might eventually control the cutworm problem. One of my local contacts suggested a heavy dose of natural insecticide. He gave me the address of an elderly gentleman with his own pyrethrum recipe. Now I considered myself sufficiently knowledgeable to dismiss pyrethrum for treating cutworm. A significant dose might control caterpillars and leafhoppers, but would probably be ineffective against serious cutworm infestations, I predicted. Natural pyrethrum breaks down to nothing within a few days. “Cutworm”, I asked doubtfully, “you’re convinced this will control cutworm?” The old gentleman touched his nose. “Yeah”, he said. “It’ll get ‘em”.

And it did! Within several days the cutworm were history. After that result I returned with a few questions. The pyrethrum supplier referred me to a publication on natural garden sprays. It was currently out of print, so with his permission I reproduced a couple of sections for my own reference. There was an insightful chapter on safety precautions required for the preparation and application of natural garden remedies. I was concerned by the toxicity of several plant derived insecticides, particularly the nicotinic and anabasinic compounds.

Nicotine-based insecticides are extremely poisonous to humans, domestic livestock, pets and native animals. Thankfully, I’ve managed to avoid these particular compounds, although many of my friends have recommended them to me. I prefer relatively safe natural compounds such as rotenoids and pyrethroids. These can still occasionally be purchased from local garden centres and organic suppliers.

It appears that toxicity of natural rotenoid compounds was initially exploited by indigenous South American tribes who used various plant extracts to paralyse fish. Organic gardeners may be familiar with the insecticide products based on these compounds. Derris powder is the most popular extract from plants of the genus rotenone. The product is still prepared by mixing the finely ground plant roots with a clay base. When sprayed appropriately, derris is effective as a general insecticide. Unlike the majority of fast acting insecticides, rotenone does not function as a nerve toxin. It is believed to inhibit oxygen transport and basic energy mechanisms within cells. It is extremely toxic to fish and amphibians, so care is required when spraying near rivers, creeks or ponds.

Organic pyrethrum

Organic pyrethrum is the botanical extract from pyrethrum flowers (chrysanthemum cinerariaefolium). This is distinct from synthetic pyrethroids which are chemical approximations of the naturally occurring compounds.

When formulated as liquid or aerosol, natural pyrethrum compounds prove rapidly effective against a wide range of insects. The knock down effect is particularly evident within enclosed environments such as greenhouses, propagation sheds, and indoor gardens. In higher doses, it can be effective in orchards, and other outdoor settings. Like derris, organic pyrethrum will break down completely after several days exposure to sunlight.

On the positive side, they are considered as one of the safest insecticide compounds with a low toxicity to humans and other warm blooded mammals, although some skin irritation and allergic reactions have been associated with repeated handling and use. Unwashed traces of pyrethrum compounds are usually destroyed by exposure to heat, sunlight, and other atmospheric influences. Negatively, pyrethrum is toxic to fish, amphibians and indiscriminate applications can obviously harm beneficial insect organisms such as pollinators and natural predators.

Since my encounter with the cutworm, I’ve received numerous enquiries about the availability of natural pyrethrum compounds. There is a general consensus that it’s becoming more difficult to obtain. Commercial crops of pyrethrum flowers are grown in Africa, Japan, and Hawaii, although the volume of production has declined significantly over recent decades. Within most organic gardening communities, there are individuals and groups who continue to raise pyrethrum chrysanthemums for the purposes of insect management. My advice is to contact the nearest organic society. They can usually provide the best indication of local availability.

Microscopic pests

The majority of nuisance insects which attack our plants from one season to the next are tiny, almost microscopic in size. Once they have identified their plant hosts, many of these pests will generate large colonies within a surprisingly short period of time. In addition to encouraging their natural predators, minute insects can be controlled with natural substances which remain effective for at least several days.

Various light oils are used to control scale, mites, thrip, flies, and many of the softer larvae which attack foliage. They work by interfering with the insects normal mechanisms of respiration, feeding, and temperature regulation. To eliminate the risk of leaf damage, these products can be sprayed when the shrubs and trees enter their dormant winter phase. Insecticidal soaps are also made from botanical oils combined with the salts from natural stearols and other fatty acids. When applied in solution to foliage, they are an effective treatment against soft-bodied thrip, mites, aphids, and flies. During times of infestation, they need to be applied several times each week although some sensitive plants can develop leaf burn with repeated applications. A weaker solution should eliminate leaf burn or assist by reducing the severity of the problem.

No magic bullet

Since committing myself to an organic approach, I’ve attempted to understand each living garden as a complex and integrated environment. Given this, I try to avoid the imbalances which can accumulate whenever insect populations are rapidly affected by toxic compounds. In short, I remain suspicious of the magic bullet approach, even when this involves natural compounds such as pyrethrum. Once again, I admit struggling to appreciate how an old-fashioned pyrethrum solution was so devastatingly effective against my friend’s cutworm problem while the contemporary chemical treatments had simply failed. The reasons were quite obvious, yet I needed time to reflect upon them.

With few exceptions, synthetic chemical products establish a toxicity which lingers in the soil for an extended period. Under these circumstances insect populations are provided opportunities to adapt, and develop their own resistance against the chemical agent. Most of the local cutworm population were probably killed through initial contact with the synthetic chemicals, although a small percentage may have survived then experienced a significantly reduced exposure over an extended period of time. It is these low level exposures which promote adaptation and, ultimately, resistance. By contrast, the residual toxicity detectable at several days following the pyrethrum treatment would have been negligible. Any surviving insects would be denied the benefits of adaptation. For this reason alone, it is often recommended that pyrethrum be used as a high potency single strike application rather than as a modest dosage regularly applied.

To date, my friend has raised many vegetable crops without the impediment of the serious cutworm infestation. We remain thankful for the effectiveness of the pyrethrum treatment although both of us believe that the decisive remedy was founded upon our integrated and longer term strategies of soil improvement and the encouragement of natural insect predators.