Most fruit trees benefit from applications of nitrogen-rich fertilizer, particularly when they are not developing fruit, or are underperforming in their rate of growth. Fertilizer helps ensure continued growth in a normalized range, as well as optimal fruit production. Fruit trees should be fed in the early spring before the buds unfurl in an amount dictated by the type of tree, fruiting condition, growth from the immediate past season and the product label recommendations.
Determine the condition of your tree and need for fertilizer by judging its relative performance. Feed nonproducing fruit trees that are growing less than 12 to 36 inches in branch length per year at the full recommended rate. Feed fruit trees that do produce fruit but are growing less than 6 and 18 inches of branch length per year using a little less fertilizer. Feed fruit trees already producing abundant fruit and growing within a normal range lightly only, if desired.
Measure the trunk diameter 1 foot above ground level. Feed with a granular fruit tree fertilizer in the amount of a tenth of a pound of fertilizer for every inch of the tree's diameter. Do not exceed a maximum of seven-tenths of a pound per inch of trunk diameter. Feed pear trees lightly at 50 percent of the rate applied to other fruit trees.
Lay down the fertilizer in a thick ring around the tree, starting at least a foot or two out from the trunk and continuing to a foot past the drip line of the tree. This will prevent burn to the trunk and central roots, and encourage outward root growth.
Water all fertilizer applications in deeply to settle the material into the soil and speed the wash of nutrients down into the soil.