Nitrogen is the most important nutrient needed. Phosphorous and potassium, are needed in relatively large amounts, particularly on young trees. After the trees mature, fertilization with phosphorus and potassium will probably not be required.
To fertilize apple trees the year they are planted, broadcast over a 2-foot circle 1cup of 10-10-10 fertilizer about one month after planting. Do not put any fertilizer in the hole before planting. In June following planting, broadcast another cup of 10-10-10 fertilizer around the tree.
In early spring of the second season (when the tree is 1 year old), broadcast 2 cups of 10-10-10 fertilizer over a 3-foot circle. Repeat this again in June.
In succeeding years, follow these guidelines for the different trees:
Standard Trees: Increase the diameter of the broadcast circle and the amount of fertilizer (10-10-10) by 2 cups per year. When the tree is 6 years old and older, only nitrogen fertilizer is needed. Use 4 cups of ammonium nitrate per tree for trees 6 to 8 years old and 6 cups for trees 9 years old and older.
If you severely prune the tree, do not apply any fertilizer that year. If growth is excessive, omit fertilizer for a year or two until growth is reduced to a desirable amount (terminal growth on bearing trees averaging 10 to 15 inches per year).
Caution: When fertilizing, never dump large amounts in a small area. Root burn may result. Also, keep fertilizer 6 inches or more away from the trunk. Always broadcast the fertilizer evenly over the recommended area.
Once the trees begin to bear, use shoot growth to determine if you need to reduce or supplement the fertilization rates previously suggested. Ten to 15 inches of growth are ideal for bearing trees. If growth is more than this, apply less fertilizer. If growth is less, apply a little extra fertilizer the next season.
Annual Fruit Production through Thinning
Apple trees grown under favorable conditions will set more fruit than they can successfully carry to maturity. The removal of excess fruit from the trees is essential to assure satisfactory development of color, shape and size of the apples remaining on the tree. Failure to remove the excess fruit will decrease flower formation for the following year and cause the tree to only produce a crop every other year.
Remove fruit by hand, reducing the apples to one per cluster with fruiting clusters spaced about every 6 inches along the limb. To remove fruit without damaging the spur or other apples on the spur, hold the stem between the thumb and forefinger and push the fruit from the stem with the other fingers. This method will remove the apple, leaving the stem attached to the spur.
The earlier hand-thinning is completed, the more effective it will be. Mid-summer thinning will help improve fruit size, but it will not aid the formation of next year’s flower buds. Most of the flower buds for next year are initiated during a four- to six-week period following full bloom, so you need to thin before this time.
How to Pick Apples
When picking apples, be careful to avoid injuring the fruit. Remove the apple from the spur by pulling upward and outward while rotating the fruit slightly. On some of the thin, long-stemmed varieties such as Golden Delicious, it may be necessary to firmly place the index finger at the point of attachment of the stem and spur to prevent the spur from breaking. Pick apples with their stems attached to the fruit; otherwise, they will not keep as long.
Diseases and Insects
A grower who produces the best quality fruit controls diseases and insA grower who produces the best quality fruit controls diseases and insects. Several of these pests damage the tree and fruit. Diseases common to apples that should be controlled are scab, black rot, bitter rot, alternaria and fire blight. Damaging insects are apple tree borers, red spider mites, scales, aphids and fruit worms
Original publication developed by M. E. Ferree, Extension Horticulturist (retired)
Courtesy: The University of Georgia Cooperative Extension