Fertilizing Fruit Trees
When planting a fruit tree, a soil test would be helpful to determine the need for adding phosphorus and/or potassium to the planting soil. These nutrients move very little in through the soil so applying them on the surface seldom corrects a deficiency in these nutrients.
Nitrogen moves through the soil to the roots where it is needed, so it can be applied to the soil surface. Apply nitrogen late in the fall or early spring before bud break to promote optimal, annual shoot growth.
Shoot growth should be:
- Non-bearing apple trees 24 to 36 inches
- Fruit-producing apple trees 12 to 24 inches
- Pear trees 12 to 26 inches
- Peaches 16 to 24 inches
Growth at less than the recommended rates results in reduced fruiting wood and less fruit production. If you're starting a fertilizer program for stone fruits such as peaches or apricots, apply nitrogen to the soil around the trees at the rate of one-eighth pound for every one inch of trunk diameter. Take the trunk-diameter measurement one foot above ground level. With apples or pears, apply one-tenth pound of nitrogen for every one inch of trunk diameter.
The amount of nitrogen needed is determined by the previous year's growth. If more growth is needed, increase the amount of nitrogen. If too much growth occurred, it's best to reduce or eliminate nitrogen. Keep records of how much and what nutrients you apply each year.
Fruit trees in lawn areas may get adequate nitrogen from applications of lawn fertilizer. In some cases, fruit trees in lawn areas grow too much as a result of excess water and fertilizer they receive from lawns. Do not apply "weed-and-feed" products because they contain herbicides that may be harmful to fruit trees. If fruit production is desired in these instances, reduce the frequency of watering and the amount of fertilizer applied to the lawn.
Excessive pruning also will stimulate shoot growth and should be avoided.
For "Organic vs. Manufactured Fertilizers" refer to message number 1619.
For more information, see the following Colorado State University Extension fact sheet(s).
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Updated Tuesday, October 13, 2015