Feeding Shrubs and Trees in Late Winter
Late winter is an appropriate time to feed tree fruits, if they need it. If the soil was carefully prepared before planting and is subsequently regularly topdressed with rotted organic mattermay not be necessary at all. However, sandy or shallow soils are likely to need annual additions of , unless you are clever with the use of manure or .
Main mineral nutrients needed are nitrogen, phosphorus and potassium and these can be obtained singly as, for example, sulphate of ammonia (nitrogen, N) or sulphate of potash (potassium, K), or as compounds containing all three in varying percentages. The percentage will be shown on the container in the form of an ‘analysis’ — thus: N 5 per cent, P** 205 (phosphorus, P) 7 per cent, K20 9 per cent, so helping you to decide which is the most suitable for your plants.
Nitrogen helps with shoot and leaf growth, phosphorus is needed by the roots and potassium is the maturing nutrient, encouraging flower and fruit production. These divisions are very general and the subject of nutrients and their interaction is extremely complex, but remembering that the above are the main roles of these nutrients, you can apply them according to whether your plants are cropping too much, moderately, or running to leaf.
Rates of application of the compound fertilizers will be given on their containers; the ‘straights’ are applied as follows:
Sulphate of ammonia (N), 15-30g per sq m (1/2 – 1oz per sq yd)
Nitro-chalk (N and lime) 30g per sq m (1oz per sq yd)
Hoof-and-horn meal (N) 60g per sq m (2 oz per sq yd)
Superphosphate (P) 30-90g per sq m (1-3oz per sq yd)
Bonemeal (P) up to 180g per sq m (6oz per sq yd)
Sulphate of potash (K) 15-30g per sq m (1/2 – 1oz per sq yd)
Wood ash (K) up to 240g per sq m (8oz per sq yd)
Nitro-chalk is a convenient way of ensuring that the stone fruits get the calcium they need but if nitro-chalk is not used, lime should be applied every four or five years or so at about 240g per sq m (8oz per sq yd), depending on the degree ofof the soil.
There are many other mineral nutrients also required by plants; some are called the ‘trace’ elements as the plant requires them only in minute quantities, to the order of parts per million, and others such as sulphur, iron and calcium are the minor elements, coming between the two. All have different functions within the plants and are dependent on one another to some extent and all are present in the average, provided it is treated with rotted organic matter in sufficient quantity to ward off deficiencies.
If the state of the soil permits, grape vines can also be fed and topdressed. Weeds, leaves, last spring’sremains and other rubbish should be raked carefully off the area beneath which the roots are growing. Then a mixture of rotted organic matter and in equal parts, combined with a proprietary vine compound fertilizer, can be spread over the clean soil surface to a depth of about 7.5cm (3in).