January 18, 2016
Sometimes, fruit trees are overachievers. One summer, a client called me to prune his apple trees. The trees had set so much fruit that their branches were breaking off. In this situation, an ounce of prevention would have been worth more than a pound of pruning invoices. And an ounce-sized fruit is exactly what you want to pick.
To keep your trees from overdoing it, thin out about half of the fruits while they’re small — less than an inch across — about four to six weeks after peak flower bloom. This will help your trees produce a smaller number of bigger fruits without compromising the entire tree or producing tons of dinky fruit.
Keeping fruit trees from this kind of self-destruction is easy enough for novices and pros; no special tools are required. A thumb and index finger are all the pruning tools you’ll need (and maybe a ladder for taller trees). This is by no means a waste. Carry the “culled” fruitlets in a bucket to the compost bin, or introduce them to the two-legged composters known as chickens. You may also want to thin the fruits so they don’t touch as they mature. Close contact among fruits helps fungus spread after a rain, and you don’t want that.
If you’re having a season of low fruit-set due to a late frost or poor pollination, you may not need to thin; nature will have taken care of that for you. You can also thin later in the season; this can still prevent broken branches and fungus outbreaks, but it may be too late for the remaining fruit to take advantage of the special treatment and fill out.
Some fruit trees rarely need thinning: figs, citrus and pomegranates. On the other hand, stone-fruit trees (plums, peaches, cherries, apricots, nectarines) and pome fruits (apples and pears) often benefit from thinning. Persimmons are borderline on whether they’ll need thinning or not, so use your judgment.