Plants need to be fed regularly with manure and fertilizers. The two are complementary and both are usually necessary for plant growth. Manure is bulky organic matter that is derived from animals or plants. It breaks down in the soil to become humus, a dark gummy substance which binds the soil particles into small groups, leaving gaps in between for air and water to circulate. The bacteria in the soil convert it to chemical salts which dissolve in water and are taken up by the roots of the plants as nutrients. Fertilizers are concentrated forms of chemical salts which provide nutrients direct to the plant but contain little or no humus.
Soft fruits in particular like a mulch of well rotted farmyard manure and all fruits require a feed in winter of top dressing. This simply means replacing the top dressing of 2,5cm with fresh compost. Your local riding school will have an abundance of manure.
Most fruit, vegetables and herbs will benefit from an application of fertilizer feed at the beginning of the growing season, usually in late spring. Throughout the growing season look out for plants showing signs of a particular nutrient deficiency, such as a lack of potassium or nitrate, and feed with a fertilizer rich in that particular nutrient. With fruit trees, wait until they reach f lowering age before feeding and take care not to overfeed or you will promote leaf growth at the expense of fruit yields.