Kootenays Gardening - Essential Substances in the Soil

Earth friendly gardening in the Kootenays region of British Columbia, Canada

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Essential Substances in the Soil

Under cultivation soils tend to lose their available plant foods. To ensure continuous supply of essential substances it is sometimes necessary to replete them by application of fertilizers. The use of organic manures and fertilizers is recommended.

Nitrogen, phosphorus and potassium are often present in insufficient amounts in the soil. In the garden practice the fertilizing routine is usually directed towards increasing the amount of these elements. For the best results, however, they should be applied in moderation.

Nitrogen	Phosphorus	Potassium
Nitrogen is vital to plant growth.	Like nitrogen, phosphorus is vital to plant growth processes. It promotes root activity and ripening of seeds and fruits.	Potassium is essential to overall plant growth and health. It is a factor in fruit trees growth and production. It increases resistance to disease and harsh weather.
Too little nitrogen causes restricted growth, stunted, thin shoots, yellowing of foliage (chlorosis) and premature leaf fall. Fruit blooms are few and fruits small and highly colored.	Too little phosphorus results in stunted root and top growth, small, dull, bluish-green, prematurely falling leaves, poor blossoming and reduced yields.	Too little potassium may result in stunted growth, marginal browning or scorching of leaves.
Too much nitrogen will produce sappy, dark-green foliage and will delay ripening of fruit. It can also contribute to the Blossom End Rot in Tomatoes, Peppers, Squash, and Melon.
Organic sources:	Organic sources:	Organic sources:
Animal manure, compost, blood meal, hoof and horn meal, fish meal, guano, soybean meal, alfalfa meal, cottonseed meal	Fish meal, guano, bone meal, wood ash, grounded rock phosphate	Animal manure, fish meal, guano, wood ash, kelp meal, leaf mold, hay and straw mulch, greensand

Other elements like calcium, magnesium and sulfur are sometimes deficient and should be added with prudence.

Calcium	Magnesium
Calcium is usually applied in the form of agricultural or garden lime, in large part composed of calcium carbonate CaCO₃	On acid soils application of dolomite lime once in a while in rotation with agricultural lime is beneficial.
Lime is a soil tonic and plant food. It also sets free other plant foods and counteracts soil acidity.	Dolomite lime should be considered as a liming agent as well as a potent magnesium fertilizer.
It renders clayey soil more friable and easier to work.	It is composed of calcium magnesium carbonate CaMg(CO₃)₂
Loose sandy soils by addition of lime become more compact and moisture retentive.	If used in excess Dolomite may cause undesirable magnesium buildup.
Calcium deficiency results in poor roots and distorted young leaves.	Magnesium is important for the proper function of photosynthesis and the production of chlorophyll. It tends to be lacking in soils with low pH.
Lime helps keep in check diseases like club rot and clover sickness and is distasteful to pests like slugs, wireworms and leatherjackets.	Some common deficiency symptoms are yellowing of the leaves between the veins, leaf curling, stunted growth, and lack of sweetness in the fruit.
Most plants need lime in order to grow. Roses, Spiraeas, Quinces, Mock Oranges, Pear and Plum trees, Flowering Crabs and Cherries, Mountain Ashes and Hawthorns do very well on lime soils. There are, however, plants like Azaleas and Rhododendrons that are harmed by lime.	Epsom salts, hydrated magnesium sulfate (about 10 percent magnesium and 13 percent sulfur), is another source of magnesium and sulfur to soils deficient in those elements. It should not be used without caution.
Majority of plants prefer soil that is neutral. Since under cultivation soils tend to become more acid it is beneficial to apply lime periodically to maintain soil neutrality. The best time to do that is in late winter or in early spring.	For use as a foliar spray mix 1 tablespoon of Epsom salts with a gallon of water. For better fruit quality spray few of your Tomatoes and Peppers at bloom time and again 10 days later. Compare the fruit produced by sprayed and non-sprayed plants.

Addition of Sulfur is sometimes needed to increase soil acidity. To decrease pH one level, 0.5 kg. of elemental sulfur should be worked into 10 square meters of soil.

There are other essential elements that are needed in extremely small amounts. They are called trace elements or micro-nutrients. Their deficiency, as well as too great concentrations, may have detrimental effect on plants. Majority of garden soils contain sufficient quantities of trace elements. Deficiency is most likely to occur on sandy soils, on muck soils, on highly alkaline soils and on soils that have been intensely cropped and fertilized with only macronutrients.

Trace elements that sometimes need to be added are boron, copper, iron, manganese and zinc. They should not be added unless a soil as well as plant tissue tests show they are needed. Consult competent gardening specialist on the amount and method of application. Too high levels of trace minerals may be toxic to plants, and in turn, to humans and animals that consume them.

The safest and most reliable way to assure a balanced ratio of macro- and micro-nutrients in the soil is by using organic mulches like compost, grass clippings, leaf mold and/or other kinds of organic materials, by application of ground limestone, seaweed, fish fertilizers and/or by growing cover crops (green manures). It is important that plant materials used as organic mulches and fertilizers are themselves free of contaminants.

Trace elements (should not be added without a soil analysis)

Boron plays a role in development of root system and formation of fruit and seed.

Deficiency may occur on dry, well-drained soils, or as a result of over-liming. It can be amended by growing cover crops like Vetch and Sweet Clover, by application of liquid Seaweed, wood ash, granite dust or by application of minute quantities of borax to the soil, at a rate of 3 dkg. per 20 sq. meters. Boron deficiency may be a reason for stunting and curd browning in Cauliflowers, heart rot in Beets, brown heart in Turnips and Rutabagas, yellowing of Broccoli heads, hollow stems in Kale and Celery.

Chlorine assists root and top growth. Chlorine is supplied in sufficient amounts by rain.

Chromium deficiency can be amended by application of liquid Seaweed.

Cobalt helps with fixation of nitrogen. Deficiency can be amended by growing cover crops like Vetch and other legumes or by application of liquid Seaweed.

Copper is a catalyst for plant respiration and synthesis of chlorophyll. Deficiency can be amended by growing certain cover crops or by application of sawdust or liquid Seaweed.

Fluorine

Iodine Deficiency can be amended by application of liquid Seaweed.

Iron plays a role in synthesis of chlorophyll. It is also a necessary element of certain enzymes and proteins. Deficiency can be amended by growing certain cover crops or by application of liquid Seaweed. Deficiency, especially on alkaline soils, results in chlorosis or paleness of foliage.

Manganese plays a role in photosynthesis, formation of carotene, riboflavin and ascorbic acid.

Deficiency is most likely to develop on wet soils and on soils with a high organic matter content, like soils derived from marsh and swamp areas. It can be amended by growing Alfalfa and some other cover crops or by application of leaf mold or liquid Seaweed. Deficiency symptoms are similar to iron deficiency.

Molybdenum plays a role in synthesis of protein and fixation of nitrogen. Deficiency can be amended by growing Vetch as a cover crop. Deficiency results in poor fruiting.

Selenium

Zinc plays a role in formation of growth hormones and in maturation of seed. Deficiency can be amended by growing Vetch and Alfalfa cover crops or by application of rock phosphate or liquid Seaweed. Deficiency is a cause of so called Little Leaf disease of fruit trees like Apples, Apricots, Peaches, Plums, and Grapes.