Fruit drop—the natural tendency for fruit trees to shed some immature fruit after flowering—protects the health of the crop. But admittedly, admiring your trees' spectacular spring flowers, seeing the tiny fruits begin to form, and then witnessing them fall in large numbers before they mature can feel devastating. However, this behavior is a biological adaptation of the species that serves its purpose.
Fruit trees often set more flowers than needed for a full crop. Fruit drop offsets the possibility of sudden loss due to inclement weather or other hardship. According to Purdue University's Consumer Horticulture website, “Only one bloom in 20 is needed for a good crop on a full-blossoming apple tree.” So fruit drop is simply your tree telling you it's healthy, while also ensuring it can sustain every fruit that ripens to maturity.
Why Trees Drop Fruit
Fruit trees start their thinning process early in the season by shedding unpollinated flowers. This rarely alarms anyone and often goes unnoticed; we chalk it up to the wind or the weather. But when fruit starts to fall, it becomes more alarming unless you understand biology.
Fruit trees set fruit to produce seeds. Too large a crop will strain the tree’s resources and result in smaller fruit that's lesser in quality. So the tree protects itself, its fruit, and its seed by automatically thinning the crop once the growing conditions are stable. Since the immature fruits are all competing for the same food and water, the June fruit drop ensures that only the strongest survive. The fruit that contains the fewest seeds is usually the first to drop.
How to Lessen Fruit Loss
Healthy trees that have stable growing situations will drop less immature fruit and yield a greater percentage of healthy fruit. Make sure your fruit trees get the right amount of water. Too little water will create stress and cause flowers to fall before pollination. Too much water can create a breeding ground for fungus or disease to set in.
But preventing fruit drop is not necessarily something to strive for; the tree and its fruit will grow best if the immature fruit is thinned slightly. In fact, stone fruit trees (peaches, plums, nectarines, and apricots) don't thin themselves enough and need additional help from us. Since each fruit only houses one seed, the tree wants to hold on to all the fruit. So, be sure to hand-thin the immature fruit of your stone fruit trees for an ample crop.
For reasons not fully understood, stone fruit trees like cherries hang onto all their fruit without any problems. It could be because the fruit itself is smaller and more plentiful than that of other varieties.
Accepting Fruit Drop
After all the worry, fruit drop is really just a normal occurrence. And it's not just good for the fruit tree; it also provides less maintenance for you. Not only will you get larger, more delicious fruit, but the branches of your trees will be lighter and less likely to break or require artificial support.
Pruning the fruit off of smaller fruit trees, removing entire limbs that are dead or diseased, or cutting the ends of branches (also known as heading cuts) will also help to keep the fruit tree healthy. A tree that is thriving will produce more abundant and larger fruit in the upcoming season.