Fruit trees require little if any fertilizer the year they are planted, particularly if you did a good job preparing the soil—adjusting pH and adding organic matter—the previous year. A starter solution applied at planting usually supplies enough nutrients for the first season's growth. In subsequent years, some fertilizer may be needed for good annual growth.

Most soils contain many of the elements essential for plant growth. Fruit trees have large root systems. Under favorable conditions, the roots tap a large volume of soil, foraging for nutrients. Fertilizer is needed only when plants are unable to get sufficient quantities of these elements from the soil. When trees can't get enough nutrients from the soil, the result can be decreased vegetative growth, light fruit set, and small fruit.

Whatever you do, don't overdo the application of fertilizers! Too much fertilizer can be as detrimental as too little, particularly when it comes to nitrogen. Nitrogen fertilizers, represented by the first number on the fertilizer

Wood chip or bark mulch is least attractive to voles.

bag, fuel the annual extension growth in the trees (see Figure 12, page 31).

Annual extension growth is the amount that a branch grows each year. Too much fertilizer

To gauge annual extension growth, measure the distance from the tip of the is as bad as too branch back to the "ring" formed by the scars from the previous year's buds little that encircle the branch, marking the end of the previous season's growth. '_

You generally should get about 18 to 24 inches of annual extension growth during the first several years. Thereafter, 10 to 12 inches is sufficient for mature trees.

As a general rule, determine how much fertilizer to apply based on the guidelines in the chart below. These are the rates that you should apply if your trees are not producing enough annual extension growth as described above.

Note that the amounts are small, but don't be tempted to overapply! Overfertilization with nitrogen, phosphorus, and potassium can cause deficiencies in other nutrients. If your young trees are growing as described above, then apply no fertilizer and reevaluate your need next year.

Ammonium nitrate

Nitrogen rate (33% N) 10-10-10 (10% N) 20-20-20 (20% N)

Young trees 0.04 lb./tree 2 0z./tree 6 0z./tree 3 0z./tree

Mature trees 0.08 lb./tree 4 0z./tree 12 0z./tree 6 0z./tree

If your trees flower every year but don't produce fruit, a micronutrient deficiency might be the cause. After eliminating other possibilities, such as late frosts, have a leaf tissue analysis done. (For more information about leaf analysis testing, contact the Cornell Nutrient and Elemental Analysis Laboratory, telephone: 607-255-1785, or via the web at www.hort.cornell.edu/de-partment/facilities/icp)

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