Fruit trees require nutrients to develop properly, so work phosphorus and potassium into the soil before you plant. The amounts you apply should be based on a soil test report. Keep in mind that these nutrients move very little in soil. Applying phosphorus and potassium to the soil surface around fruit trees, rather than into the soil itself, seldom corrects deficiencies of these nutrients.
However, you can apply nitrogen to the soil surface because it moves down to the roots where it's needed. Nitrogen can be applied late in fall or early spring. In spring, nitrogen should be applied before bud break. The amount applied depends on the type of fruit tree and its growth status. Trees should be fertilized with enough nitrogen to promote optimal, annual shoot growth.
For more information, please see the PlantTalk script #1216, Fertilizing fruit trees.
