A really easy way to tell whether your fruit trees are getting enough nutrients or not, is by taking a look at how much new growth they are putting on every year.
If your trees are being properly fed, they will put on the new growth listed here:
New Growth Per Year:
Apple Trees: 6-18 inches (15-46 cm)
Apricot Trees: 10-18 inches (25-46 cm)
Cherry Trees: 18-24 inches (46-61 cm)
Peach Trees: 6-24 inches (15-61 cm)
Pear Trees: 12-24 inches (20-61 cm)
Plum Trees: 12-18 inches (20-46 cm)
If Trees Are Growing Too Much:
Now, if your trees are growing faster than this, and putting on more growth than is listed above, you need to cut back. Simply don’t fertilize again until the trees have slowed down their growth.
Remember, too much tender new growth in very susceptible to insect and disease problems, and, it can increase how much you will have to prune every year.
If Trees Are Not Growing Enough:
If, however, your trees are not growing enough, then in the spring, when the trees start coming out of dormancy, start feeding with a good complete fertilizer like a 5-5-5 or a 10-10-10.
Any good organic food would be good, like any of the Dr. Earth fertilizers.
Have good week!