Why Are My Apricots Cracking Before Ripening?

Skin cracking on apricots in the weeks before harvest ruins what would otherwise be good fruit. The cracks allow brown rot, grey mould and insects to enter the fruit flesh, and cracked apricots will not store at all. The crack usually appears along the suture — the line running from stalk to tip — or radiates out from the stalk cavity. In almost all cases, the cause is a sudden change in the rate at which the fruit expands, which stretches and splits the skin.

The watering-irregularity mechanism

The apricot skin grows at a relatively steady rate during fruit development. When water availability is restricted — a dry spell in July, a period of neglected irrigation for a wall-trained tree — the fruit flesh inside slows its expansion. When water then becomes suddenly available again — heavy rain, irrigation resumed — the flesh resumes growth rapidly, expanding faster than the skin can accommodate and splitting it. The longer the preceding drought, the more severe the splitting when water is restored.

Prevention: consistent watering

Water wall-trained apricots deeply and consistently from fruit set through to harvest. In dry conditions this may mean watering three times per week for container trees and once or twice a week for those in the ground. Do not allow the soil to dry out completely and then flood it — this extreme variation is what triggers the most severe cracking. Apply a thick mulch of composted bark or wood chips around the root zone to buffer soil moisture fluctuations. Drip irrigation systems are particularly effective at maintaining consistent moisture levels.

Calcium deficiency

Calcium is essential for cell wall strength in fruit skin. When calcium is deficient, the skin is weaker and more prone to cracking under the pressure of rapid fruit expansion. Calcium deficiency in apricots is usually a result of irregular watering rather than a lack of calcium in the soil — calcium is mobile in water and moves through the plant with the transpiration stream, so drought disrupts its uptake and distribution. Foliar sprays of calcium chloride solution (0.4% strength) applied every ten days from fruit set to mid-August help in consistently deficient trees.

Protecting ripening fruit from rain

A polythene or glass cover over a wall-trained tree protects ripening fruit from heavy rain in July and August that causes sudden uptake of water through the skin (direct rain absorption) as well as through the roots. Temporary lean-to structures of clear polythene over wall-trained trees are simple and effective.