Preventing Tomatoes From Cracking and Splitting

After months of anticipating ripe, sweet tomatoes, my first harvest came a week ago. Unfortunately, several of the inaugural ‘Sun Gold’ cherry tomatoes were cracked around the equator, exposing healthy flesh underneath. Why did this happen and how can it be prevented?

Cracks and splits are a fairly common occurrence. They can start at the stem and run down the side of the fruit, or circle the width of the fruit, like mine did. The good news – the fissures are not the result of a disease, virus or insect. The cause? At least in part – me! On the bright side, I can easily fix it.

Tomatoes crack due to fluctuations of moisture and/or temperature that occur when the fruit is nearly fully mature. In my case, forgetting to water or underwatering a container grown plant on the first few 100 degree days, followed by “forgive me” overwatering for the next few days is the culprit. (Another tip – tomato plants don’t like to get heat wilt. Mine did that too.)

Here’s what happens to cause the fruit to split – during the dry spells, the exterior skin (epidermis) of the fruit toughens. When the plant is watered again, the fruit rapidly takes in the moisture and the fruit plumps up. This expansion causes the toughened skin to burst. Cherry tomatoes and large beefsteak varieties are particularly prone to these stretch or growth marks.

These tips will help prevent tomatoes from cracking and splitting:

  • Tomatoes like consistent moisture at regular intervals. Think of Goldilocks – not too much, not too little. Sounds simplistic, but the point is there’s a delicate balance. Watering on a regular schedule really helps.
  • Use natural mulch such as grass clippings or shredded leaves to keep the plant roots cooler.
  • Fertilize with low dose, slow-release fertilizer; high nitrogen fertilizers stimulate growth which can increase cracking.
  • Pick fruit just before it is fully mature and allow it to ripen on a sunny windowsill.

Some tomato varieties are bred to have more flexible skin and therefore are less likely to crack. When researching next year’s garden tomatoes, look for varieties labeled crack or split-resistant. You may want to give them a try.

Perhaps most importantly – is it OK to eat a cracked tomato? It really depends. Don’t take a chance if the split is deep, the fruit has been on the vine for a long time or you simply aren’t sure. Bacteria can develop in the opening with time. But if the crack has just appeared and the fruit looks healthy despite the scar, it is likely fine. Did I eat mine? I did. And it was worth the wait!

Additional reading: https://hortnews.extension.iastate.edu/faq/why-are-my-tomatoes-cracking

Photo Credit: Pixabay.com

Posted by Linda McDonnell, Denver County Master Gardener

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