Knowledgebase

How do I avoid biennial apple production? #284003

Asked October 11, 2015, 1:45 PM EDT

My golden delicious apple produces apples every other year. Is it in need of additional fertilizer? Or is this normal?

Salt Lake County Utah

Expert Response

Golden Delicious is a great apple, partially self fruitful and easy to grow. One drawback is a strong tendency to biennial bearing, when the tree produces a lot of fruit one year and very little the next. In biennial bearing apple varieties the presence of a fruit with seeds on the spur suppresses the formation of a flower bud to bloom the next year on that spur the next year. The tree also has a tendency to grow a little in the on year and a lot in the off year. In the one year you get a lot of small fruit and in the off year you get a few very large fruit. Commercial growers overcome that tendency to biennial bearing by chemically thinning the fruit to reduce the number of fruit and even out annual production. One thinner that is available to homeowners is the insecticide Sevin. You can use the labled rate for Sevin (read and heed the label) for fruit thinning even thought commecial fruit growers use less as Sevin is only a mild thinner and it is hard to overdose the trees. Apples should be thinned soon after bloom and the best results are when the fruit are 1/4 to 1/2 inches in diameter. After the tree has finished blooming watch the weather for warm days with highs above 70. Try to apply the thinning spray at the beginning of a warm spell rather than in the middle or end. The spray still works until the fruit are about an inch in diameter about a month after bloom. There is a natural wave of fruit drop called June drop that occurs at the same time and the thinning sprays enhance it. After the June drop, you need to thin the fruit by hand. Break off the fruit with your fingers at the end of the stem. You need to thin off all the fruit on most of the clusters leaving only the largest fruit spaced about 6 inches apart on the limb. You might want to concentrate on single limbs in the one years to move the tree to more regular bearing. Often a single devastating freeze that kills the blossoms one year will set an entire regions apple crop into a biennial bearing cycle of large crops one year and small crops the next.
Mark Longstroth Replied October 12, 2015, 10:47 AM EDT

Loading ...