Soil Preparation and Maintenance

Soil Preparation and Maintenance

The soil is the basic raw material of the gardener’s art. It should never be dismissed as a mere collection of mineral particles used to anchor roots or, worse still, as “dirt.” It is much more than that.

Certainly, its basic structure consists of rock particles broken down by frost and thaw action, wind, and river flow, to produce the different soil “types” (clay,” sand, and so on). However, a large part of its make-up is organic matter — vegetable and animal remains in various stages of decay — along with air and water, all essential for the support of plant and animal life. All of this provides a home for millions of living organisms, such as soil fungi, algae, bacteria, insects, and worms, which work to provide just the right conditions for healthy plant growth. It is perhaps in the treatment of soil, more than anywhere, that organic gardening differs from other gardening methods.

The very first principle of organic gardening is to nurture and encourage this subterranean life so that it can support a much larger plant population than nature ever intended.

 Few gardens can produce enough waste organic material to be self-sufficient in compost. But a remarkable amount of good stuff that is thrown away can be “harvested” by the organic gardener. The local grocer or produce market after closing time on Saturdays is an excellent source of green stuff. The local sports ground or golf club often have no means of disposing of massive amounts of grass cuttings and would be delighted to have them cleared away. Another excellent source of free soil conditioner could be a tomato nursery which grows in peat bags and has surplus at the end of the season.

 Obviously, the first requirement for good compost is something to compost. Then the heap needs air, nitrogen, lime, water, heat, and bacteria. There are a great many old wives’ tales about what can and cannot be used, but the rule is very simple: anything entirely organic in origin can be composted — with a few exceptions.

Before deciding on any soil-feeding regime, you must first discover whether the soil is acid or alkaline. Acidity or alkalinity of soil is determined by its lime content, measured in units using the pH tests. The pH is measured in units on a scale of 1 to 14. Neutral soil has a pH of 7; anything above that is alkaline and anything below it, acid.

 All plants need oxygen, carbon, and l hydrogen, which they obtain from the air, sunlight, and water. However, just as important for growth is the presence of a range of chemical elements in the soil. These are divided into the major elements (nitrogen, phosphorus, potassium, magnesium, calcium, and sulphur) and trace elements (needed in very small amounts but nonetheless essential). Oxygen, hydrogen, and carbon are needed in very large quantities. By comparison, the other nutrients are needed in much smaller amounts, but still in specific proportions: too much of one can inactivate another. For example, too much potassium can inactivate magnesium.Major elements nitrogen (N), phosphorus (P), and potassium (K) are the major elements needed in the largest quantities. These are present in all general fertilizers, some of which also contain magnesium (Mg). Most soils have adequate levels of calcium and sulphur, which can be retained by regular additions of organic matter and by using good cultivation techniques.

Nitrogen One of the most important plant foods, a component of chlorophyll — the pigment which gives plants their green color — and a vital part of the structure of plant protein. It is responsible for growth of shoots and leaves.Deficiency is not unusual because nitrogen is easily lost by leaching in open soils and can be depleted by digging in unrotted material. With a deficiency, leaves turn yellow, particularly the older ones, and plants are stunted. Too much nitrogen causes plants to grow too quickly, with an abundance of “soft” leaves, often darker green than normal. The softer growth will be liable to an insect and frost attack.Treating deficiency: Apply a fertilizer high in nitrogen, such as dried blood.

Phosphorus The next most important element after nitrogen, phosphorus is needed in smaller quantities (only about one-tenth of the amount). Phosphorus, or phosphate, is mainly responsible for good root growth, so a deficiency causes slight stunting of the plant. It can be diagnosed by distinct blue, which affects the older leaves first. Sometimes the leaves darken and develop a blue/green tinge. Also, the plant’s root system is likely to be underdeveloped.Treating deficiency: Apply a dressing of bone meal fertilizer.

Potassium Also known as potash, this is required in the same quantities as nitrogen. It affects the size and quality of flowers and fruit, and is essential for the synthesis of protein and carbohydrates. Deficiency results in small, inferior flowers and fruit, and stunted plants. Older Leaves have yellowing around the edges, followed by brown scorching. Leaves may also become bluish and eventually bronzed all over. With excess potassium, plants are not able to take up magnesium and could cause an imbalance with other elements.Treating deficiency: Apply a dressing of rock potash.

Magnesium Another element needed in much larger quantities than many gardeners realize, magnesium should be present in about the same quantities as phosphorus. It is also a constituent of chlorophyll, so deficiency causes yellowing, which starts between the veins of the leaves. The deficiency generally affects older ones first. Magnesium deficiency is sometimes caused by plants not being able to take up the magnesium in the soil, perhaps because too much potassium is present, or because soil structure is poor, if there is insufficient organic matter in the soil.Treating Deficiency: Apply a dressing of seaweed meal, liquid seaweed, or liquid animal manure.

Calcium Another element required in relatively large amounts, calcium neutralizes certain acids formed in plants and helps in the manufacture of protein. Deficiency is rare in a well-managed organic garden, but plants sometimes develop an inexplicable inability to distribute calcium through their systems, though no one really knows why this occurs. The classic example is blossom-end rot in tomatoes, when the tip of the fruit blackens and rots. Lack of calcium also causes tip-burn on lettuce, black heart in celery and browning in the centers of Brussels sprouts. Deficiency is most pronounced in young plant tissue.Treating deficiency: There is no specific cure for calcium deficiency. Use such lime sources as wood ashes, hydrated lime and oyster shells, and build up a balanced nutrient level in the soil.

Sulphur Sometimes classed as a trace element, although sulphur is needed in fairly large quantities. Sulphur forms part of many plant proteins and is involved in the formation of chlorophyll. Sulphur deficiency causes plant stunting and yellowing of the plant, but the problem is rare since there is generally enough sulphur in organic soils because of the regular applications of compost and manure. Treating deficiency As soon as you notice a sulphur deficiency, apply a very light dusting of calcium sulphate (gypsum) over the soil surface.

Trace Elements Needed in very small quantities, but vital to plant growth. The six of major importance are iron, zinc, copper, manganese, boron, and molybdenum. In an organic garden, deficiencies are extremely rare because all the trace elements are present in compost, manure, and other bulky organic matter. Problems can occur when the action of trace elements such as iron, manganese, and boron is inhibited by alkaline, or limy soil, resulting in yellowing of rhododendron leaves and between the leaf veins in raspberries. It is best to prevent trace-element deficiencies occurring at all, normally quite easily achieved by continued use of bulky organic matter. Where deficiencies have occurred, treat soil annually with seaweed meal fertilizer.IronNeeded to make chlorophyll. Deficiency shows as yellowing between leaf veins, especially younger ones. More likely on alkaline soils, sometimes looks like magnesium deficiency.Treating deficiency: Spray with liquid seaweed, apply seaweed meal and/or manure.Zinc and copper A deficiency of either makes younger leaves mottled yellow; citrus trees develop “little leaf”.Treating deficiency: Dress with seaweed meal, compost, or manure.ManganeseNecessary for chlorophyll and protein. Deficiencies (stunting and yellowing of younger leaves) show more on alkaline soils.Treating deficiency: Spray with liquid seaweed; apply seaweed meal, compost, or manure.BoronImportant to growing tissue. Deficiencies more likely on alkaline soils: lead to a tissue breakdown: internal “corkiness”, especially in apples and many root crops, and brown-heart in celery and brassicasTreating deficiency: Once apparent, it is too late to save the crop. To protect next crop, apply seaweed meal, compost, or manure.MolybdenumUsed in protein production; deficiency shows as deformed growth, causing “whiptail” in brassicas (leaves become thin and strap like). Deficiency due to acid soil conditions.Treating deficiency: Add lime to raise pH. Spray plants with liquid seaweed fertilizer, dig in seaweed meal, and/or compost, or manure to the soil.google_ad_section_end

Green Manure This is a crop grown to add organic matter to beds that are empty for a period of time. It is sown specifically for digging into the soil to provide organic matter and plant food. It is also able to make plant nutrients available, so that when it is dug in they are nearer the surface and accessible to the next crop of plants.

Using Animal Manure for Organic Gardens start Animal manures are the very best sources of organic matter for your soil, though more difficult to obtain than compost. Manure can be used on any soil, not only to improve its condition, but also to feed it with nutrients. Use some, like poultry manure, with care because of their high nitrogen content.

Alternative Soil Conditioners for Organic Gardens Apart from compost and manure, many other organic materials can be dug into your soil or used as a mulch to help improve drainage or water-holding capacity, depending on the soil type. These materials should be looked upon only as soil conditioners: although some contain plant nutrients, they are not present in large enough.

Improving Garden Soil the Organic Way start All soil types benefit by the addition of bulky organic matter such as well-rotted compost or manure. This is the key to soil fertility and a healthy, fertile soil is the basis of the organic approach to gardening, and indeed the basis of all good gardening, organic or not.

Organic Fertilizers There is no scientific evidence to suggest that yields will be significantly heavier or that fruit and vegetables will actually taste any better if the plants are fed with organic nutrients instead of inorganic ones. The reason there is no scientific evidence is that, so far, there has been no research done on the subject. Most organic gardeners will assure any scientist, however, that he or she will certainly notice a difference in the taste of organically grown potatoes and vegetables compared to the inorganically grown ones found in the supermarket.

Fertilizers in Organic Gardens The use of concentrated fertilizer is probably one of the most controversial areas in organic gardening. Some gardeners claim that additional fertilizer is unnecessary with correct cultivation methods. Others employ methods identical to the chemical grower except that the products used are organic in origin.
Plants need a wide and varied range of nutrients to be present. Chemical growers supply those needs as immediately available fertilizers. The soil simply holds the nutrients, but then becomes devoid of life, and the lost nutrients must be replaced every year. Organic gardeners feed soil rather than plants. If high soil-fertility levels are maintained by regular additions of organic matter, the plants can simply draw on the material as required. All necessary nutrients will be added if you manage the soil as on pages 64-65. There is no danger of an overdose and a steady supply is ensured by all the various soil organisms.

Maintaining Good Soil for a Garden The ideal soil has a good crumbly structure, is rich in organic matter, drains enough to prevent topsoil becoming waterlogged in heavy rain, and provides the nutrients for healthy plant growth.

What is Soil?  Soil is formed over millions of years by the physical or chemical weathering of rock. Clay soils are formed by chemical weathering, where the mineral composition of the rock is changed, usually by the action of weak acids. Other types of soil are the result of physical weathering, which mechanically erodes the soil either within the rock or externally.

Worm-Worked Compost Earthworms can be put to work by the organic gardener in the soil, compost or manure with highly beneficial results. Worms feed mainly on organic matter and, in the process, break the waste down and eject it as pellets. The resulting crumb structure helps to improve soil drainage and aeration and therefore provides a superior environment for root growth. Pellets also change nutrients in organic matter into a form readily available to roots. At the same time the water-holding capacity of the soil is increased considerably. The worms also produce enzymes which enable bacteria to work more efficiently, so the presence of worms in the compost or manure heap accelerates the decomposing process.