Fruit thinning should be done just after the June apple drop, when the fruit is about the size of a cherry or walnut. For most varieties, the apples are removed but the stems stay attached to the fruit spur. Thin to have about 6 inches between the fruiting cluster, leaving one or two of the largest fruit per cluster. Leaving one apple per cluster can help reduce codling moth infestations. Thinning should be done to allow a closer spacing near the base of the branch and a wider spacing near the tip. This is done to avoid having the branches bend or break from too much weight.
Early thinning or overthinning may increase the incidence of disorders such as bitter pit, but delayed thinning can reduce fruit size and return bloom.
