Plot · field guide
Why Your Tomatoes Are Cracking and Splitting
You watch a tomato ripen for weeks, then a heavy rain hits and the skin splits open. Cracking is not a disease and it is not bad seed. It comes from swings in water. The good news is the fix is cheap and simple: keep the water steady and pick ripe fruit before a downpour.
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Why tomatoes crack
A tomato cracks when the inside swells faster than the skin can stretch. After a dry spell, a big drink of water rushes into the fruit. The inside grows quickly, the skin cannot keep up, and it splits.
That is why cracks so often show up the morning after a heavy rain, especially on fruit that is almost ripe. The riper the tomato, the less its skin can stretch, so ripe fruit splits first.
The two kinds of cracks
There are two patterns, and both come from the same cause.
- Concentric cracks: rings that circle the stem end, like ripples in a pond.
- Radial cracks: lines that run down the sides from the stem toward the bottom. These are usually deeper and let in rot and bugs faster.
Keep the water steady
Even watering is the whole fix. When the soil never swings from bone-dry to soaking, the fruit grows at a steady pace and the skin keeps up.
Aim for about 1 inch of water a week, and try to deliver it on a schedule instead of in feast-or-famine bursts. A drip line on a timer makes this nearly automatic and takes the guesswork out.
- Give about 1 inch of water a week, spread across the week, not all at once.
- Mulch 2 inches deep to hold soil moisture even between waterings and rains.
- Water at the base, in the morning, so the plant is not swinging wet to dry.
Pick ripe fruit before heavy rain
You cannot stop the rain, but you can beat it. When a big storm is in the forecast, pick tomatoes that are ripe or nearly ripe. A tomato that has started to color will finish ripening on the counter in a few days, and it will not split there.
This one habit saves more fruit than anything else during a wet stretch.
Can you still eat a cracked tomato?
Yes, if you catch it early. A fresh, shallow crack is fine. Cut around it and use the tomato that day, because an open crack lets in mold and insects fast.
Toss any tomato where the crack has gone soft, moldy, or is oozing. When in doubt, cut it open and look inside before you eat it.
Keep going
Questions, answered straight
Uneven water. After a dry spell, a big drink or heavy rain makes the inside swell faster than the skin can stretch, so it splits. Ripe fruit cracks first because its skin stretches least.
Keep the water steady at about 1 inch a week, mulch 2 inches deep to hold moisture even, and pick ripe fruit before a heavy rain. A drip line on a timer makes steady watering nearly automatic.
Concentric cracks ring the stem end like ripples. Radial cracks run down the sides from the stem and are usually deeper, letting in rot and bugs faster. Both come from uneven water.
A fresh, shallow crack is fine. Cut around it and use the tomato that day, since the open crack lets in mold and insects. Throw out any that have gone soft, moldy, or are oozing.