A heavy crop requires thinning, which means removing most of the fruit while it is still small. Otherwise, the fruit does not size well nor develop best fruit quality; the tree simply can't do all the work. Heavy crops can also lead to limb breakage, alternate bearing (too much fruit one year, too little the next) and a weakened tree that is more susceptible to pest damage.

For best results, pome fruits should be thinned when about 1/2" to 1" in diameter, stone fruits when 3/4" to 1".

Most apricots and plums should be thinned to one fruit every 3-4 inches, peaches and nectarines to one fruit every 5-6 inches. Apples and pears are thinned to one or two fruits per cluster, with at least six inches between fruits when the total crop is heavy.

If a too-heavy crop is due partly to too much fruiting wood on the tree, some of the thinning can be quickly done with pruning shears, perhaps as a part of an early summer pruning.

For information about summer pruning, see Backyard Orchard Culture.