There are some who have said that in time artificial fertilizers will be used to replace organic manures entirely. Practical gardeners, however, know that humus is all important, and that if the culture of plants is to be kept at a high level and the soil improved, then the application ofor organic manures is an absolute necessity; but that organic fertilizers can be used in addition to meet the plant’s extra requirements. Once the has been provided then the organic fertilizer can play a part in stimulating crops.
Organic fertilizers can be roughly divided into three, nitrogen, phosphates and potash. Each has a part to play in building up perfect . These three main plant foods should be present in the right proportions. They are (1) Nitrogen, which has to do with the building up of the and green of the plant. It is when, however, too much nitrogen is given all the energies of the plant may be directed towards rank shoots and , with the result that its floriferousness is impaired. (2) Phosphates which mainly affect the growth and help to hasten earlier flowering, giving steady, firm continuous growth, and (3) Potash which plays an important part in the production of sturdy firm plants with blooms of a better colour, and it is said a better scent. Plants grown without sufficient potash may have softish leaves that easily succumb to disease.
The Organic Fertilizers Available
Nitrogenous Dried Blood is the commonest organic fertilizer supplying nitrogen only. It is rather expensive and is used at 70 g/m2 (2 oz per sq yd) as a rule. Soot is the alternative – preferably old soot – and used at 105 to 140 g/m2 (3 to 4 oz per sq yd).
Phosphates Bone meal is the organic fertilizer most used. It supplies phosphates slowly. It is usually used at 105 to 140 g/m2 (3 to 4 oz per sq yd). Steamed Bone Flour is sometimes applied at 105 g/m2 (3 oz per sq yd). It is very slow in action and so its use is generally restricted to the permanent crops like shrubs, roses and perennials. Potash Wood Ashes are almost the only natural form of potash. They are applied at 210 to 280 g/m2 (6 to 8 oz per sq yd) generally speaking. N.B. It used to be possible to obtain potash made from grape skins in quite large quantities. It is hoped that this organic fertilizer will be available again.
Compound Organic Fertilizers
Fish Manure Usually contains 5% nitrogen and 6% phosphates and sometimes 6% of added potash in the form of flue dust or the like.
Hoof and Horn Meal Contains 4% of Nitrogen only and this is released slowly.
Blood and Fish Bone Contains 5% of Nitrogen, 9% Phosphates, and 5% Potash. This is well balanced organic fertilizer for the flower grower.
Seaweed Fertilizer Is low in the macro-nutrients probably 1% Nitrogen, 1% Phosphate and 1% Potash but it contains an abundance of the micro-nutrients. Fortified Seaweed Fertilizer Is far richer in plant foods – the analysis being 6% Nitrogen, 7% Phosphates, and 4% Potash plus of course the micro-nutrients. It is deservedly very popular.