Fruit splitting

also called Cracking, Fruit cracking

Skins that split or crack open when a sudden rush of water swells fruit or roots faster than the skin can stretch.

Disorder Disfiguring Doesn't spread

What you'll see

Splits in the skin, often ring-shaped around the shoulders of tomatoes or running lengthways on roots
Cracking appears within a day or two of heavy rain or watering after a dry spell
Cherries, plums and grapes split at the point where water pools
Cabbages and Chinese cabbage burst from the center; carrots and swedes crack along their length
Open wounds soon attract mold, wasps and rots

Why it happens

When plants have been short of water and then get a sudden flush — from rain or a good soaking — the flesh takes up water and swells faster than the skin or bark can grow to contain it, so it splits. Ripe fruit with an already tight skin is most vulnerable.

Classic after a dry spell broken by heavy rain, or when a gardener drenches a wilting plant. Warm, wet nights and fruit left to ripen fully both raise the risk, as does a sudden growth spurt in maturing cabbages.

Treating it

Pick split fruit promptly and use or compost it before rots set in
Cut out and remove burst cabbage heads that have started to rot
Keep an eye on split fruit for wasps and brown rot in warm weather

Keeping it away

Water regularly and evenly rather than letting plants dry out then flooding them
Mulch to buffer the soil against sudden changes in moisture
Harvest ripening cherries, tomatoes and cabbages before forecast heavy rain
Grow crack-resistant varieties where splitting is a yearly problem

Who gets it

Tomatoes, cherries, plums and grapes split above ground, while cabbages, carrots, swedes and radishes crack at the root or head.