An apple a day is not possible if you only get an apple every other year and that is the fate of some trees. Biennial bearing or a high crop followed by virtually no crop is not the sort of apple production a gardener needs.

Causes of Erratic Fruiting

• Some types of apple cultivars are more prone than others to fruiting only in alternative years. Beauty of Bath and Laxton’s Superb naturally tend to fruit biennally.
• Trees can be tipped into biennial mode by frost when no pollination takes place.
• No crop, high crop, no crop becomes learnt behaviour
• Heavy crop during an on year depletes the resources and the tree takes a rest or year out
• Keeping too much old wood reduces new wood and can lead to biennial bearing.
• Cropping patterns are internally regulated by the tree.

Solutions to Erratic Apple Bearing

• Select varieties and pollinators with care.
• Thin out the flower clusters leaving only 10% of the flowers to shock the tree and modify its behaviour. It may take several seasons.
• Water your trees and look after them during both years.

Other Comments

• Apple trees  initiate flower buds for next season’s crop in the current season.
• An alternation of large and small crops can be caused by competition between the current season’s crop and the coming season’s flower buds.
• Seed-produced hormones from the developing ovules have an inhibitory effect on flower development. Apple may be prone to this floral inhibition.