Tomatoes splitting their skins
This summer, I planted two varieties of small (cherry) tomatoes. They grew well and flourished, but as they ripened, a large fraction of them had split their skins. This was true even of some that were not yet ripe. Oddly, even a day or so after harvesting only those with intact skins initially, I found many would split their skins over a period of hours following harvesting. What's going on, and how can I prevent this in the future? My location is about a mile south of the St. Paul campus. My soil is only fertilized with compost from the leaves that drop from our trees each Fall. With the fairly rainy summer we had, I only needed to water the plants a few times during the summer, and never watered in the latter part of the summer.
Ramsey County Minnesota
Thank you for the question. With the abundant rainfall this year, many people experienced splitting of their tomatoes.
The most common cause of splitting in tomatoes is environmental stress. As the tomatoes mature the skins get harder. If the plant gets a lot of water after that point, either through rainfall or irrigation, it will take water into the fruit causing it to swell and split the skin. You might want to harvest these tomatoes a bit early and let them ripen off the vine. That way, the plant cannot add more water. When it doesn't rain so much and you have more control, avoid daily watering.
Try watering every three to four days, picking the tomatoes just before you water. When possible, harvest tomatoes if you expect a heavy rain.
Here's what the University of Minnesota says about it:
Thank you for contacting Extension.