The fertilizer needs of fruit trees will vary depending on the type of tree and soil conditions, but all fruit trees require large amounts of nitrogen to grow well and produce fruit. Therefore, fertilizers high in nitrogen are the best for fruit trees.
Fruit trees also require phosphorus, potassium and a variety of other trace minerals to grow properly. A zinc foliar spray is also recommended for most fruit trees on an annual basis to keep the trees growing and producing fruit. Good commercial fertilizers that incorporate each of the main elements are available from garden centers and nurseries. State university extension offices can also recommend blended fertilizers that best address the needs of specific fruit trees in a particular area.