Why Are My Tomatoes Cracking? Growth Cracks From Uneven Water

Why the fruit splits

Cracks come in two patterns: radial cracks that run out from the stem end, and concentric cracks that circle the fruit in rings. Iowa State Extension attributes both to wide fluctuations in soil moisture, with the classic trigger being a heavy rain or a deep watering after a long dry stretch. The sudden flush of water makes the fruit's interior expand quickly, and the skin, which grows more slowly, tears.

This is why cracking often shows up right after a summer storm, and why it concentrates on fruit that is at or near ripening when the moisture swing hits. It is a physiological disorder tied to growing conditions, so there is no spray for it; the lever you control is how steady you keep the soil moisture.

How to prevent cracking

• Water consistently. Iowa State suggests a thorough soaking about once every 7 days during dry weather rather than frequent shallow sips or long dry gaps followed by a flood.
• Mulch around plants with straw, shredded leaves, dried grass clippings, or similar material to conserve moisture and even out swings.
• After a dry spell, ease water back in gradually instead of saturating the bed all at once.
• Choose crack-resistant varieties if it recurs; Iowa State lists 'Jetstar,' 'Mountain Spring,' and 'Mountain Fresh,' and notes cracking is most common on large beefsteak types.
• Pick fruit as it ripens, before a forecast heavy rain, so it is off the vine when the moisture surge arrives.

Sources

Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.

• Iowa State University Extension - Why are my tomatoes cracking? — Cracking is associated with wide fluctuations in soil moisture; a heavy rain or deep watering after a long dry period causes rapid water uptake and cracking. Prevent it with consistent moisture (a thorough soaking once every 7 days) and mulch; crack-resistant varieties include Jetstar, Mountain Spring, and Mountain Fresh, and cracking is most common on large beefsteak types.
• N.C. Cooperative Extension (Rowan County) - Why Are My Tomatoes Cracking? — Tomato cracking (radial and concentric growth cracks) results from rapid water uptake when the fruit interior expands faster than the skin, most often after rain following dry conditions; even watering reduces it.
• RHS - Tomato Splitting and Cracking — Fruit splits when irregular watering causes a sudden surge of water into the fruit that the skin cannot accommodate; maintaining consistent watering helps prevent it.

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