Major elements in your soil

Nitrogen(N); Phospherus (P) and potassion (K) are the elements which are most needed in the soil for healthy plants. They are present in all fertilisers. Some fertilisers also contain magnesium (Mg) which together with calcium completes the major elements in the soil.

Nitrogen is one of the most important foods for plants. It is a component of chlorophyll – the pigment which gives plants their green colour. It is also a vital part of the structure of plant protein.Nitrogen is the element which is responsible for the growth of shoots and soft leaves in plants, so you can see how vital it is. It is not unusual to have a Nitrogen dificiency in your soil because it is easily leached out in open soils and can be depleted by digging in unrotted material. You can tell if you have a deficiency becuaes plant leaves will become yellowed, particularly older ones. Plants will also become stunted. Too much nitrogen will have the opposite efect, plants will grow too quickly and the leaves may be a darker green than usual. The softer growth will mean the plant will be more liable to attacks by insects and frosts. If you have a nitrogen deficiency treat your soil to a high nitrogen fetiliser such as dried blood.

Phosphorus is the next most importrant element in your soil. It is needed in smaller quantities than nitrogen (about a tenth of the amount) but is nonetheless very important. Phosphorus (or phosphate) is responsible for good root growth so a deficiency causes a stunting in the plant’s growth. It is easily diagnosed by a distrinct blue colour which affects the older leaves first. Sometimes the leaves darken and develop a blue/green tinge. In addition, the root system will be underdeveloped. Treatment for a phosphorus deficiency is easy – apply a dressing of bone meal fertiliser.

Potassium is also (-perhaps better) known as potash. It is required in the same quantities a nitrogen and it affects the size of the fruit and flowers. It is essential for the plant’s making protein and carbohydrates. If you have a potassium deficiency the plants themselves may be stunted or you may have smaller, inferior flowers and fruit. It also shows up in older leaves as a yellowing around the edge of the leaves followed by brown scorching. Alternately the leaves may become bluish and eventually bronzed all over. An excess of potassiumm may mean that plants cannot take up magnesium and could cause an inbalance of other elements. If you have a possium deficiency, apply a dressing of rock potash.

Magnesium is another element which is required in much larger quantities than many gardeners realise. It should be present in about the same quantity as  Phosphorus. It is a constituent of chlorophyll so a deficiency shows as a yellowing of the leaves starting at the veins. Deficiency of magnesium generally affects older leaves first. However, a magnesium deficiency in the plant may not mean that there is a deficiency in your soil, merely that the plant cannot take it up becuise there is too much potassium present. This can also happen if there is insufficient organic matter in your soil. Treatment for a magnesium deficiency is to apply a dressing of seaweed meal or liquid animal manure.

The last major element is Calcium. It is required in relatively large amounts and neutralises certain acids formed in plants. It also helps in the manufacture of proteins. Calcium deficiency is rare in well managed organic soiils but plants sometimes develop an inability to distribute calcium throigh their systems.The classic example of this is blossom end rot in tomatoes when the tip of the fruit blackens and ro(If this happens just pick the fruit off and dispose of it – it is not contagious). Lack of calcium also causes to burn in lettuces, black heart in celery and browning in the centre of brussel sprouts. There is no specific cure for calcium deficiency. The only answer is to treat your soil right. Incorporate plenty of manure and compost in your soil to build up a balanced nutrient level.

In fact, that last sentence applies to some extent to all deficiencies. Before planting, always ensure that your soil has plenty of compost and manure. Nothing beats good soils to produce good plants. Prevention is always better than cure.