Why do tomatoes split?

If you grow your own tomatoes (or buy them from your local farmers' market), you might notice that some ripe tomatoes have a split or two in their skin. Sometimes, people notice that their tomatoes tend to split following a heavy rain, or in specific spots on their tomatoes, such as near the stem. While it can make you question your green thumb (and also whether or not you should eat them), there are a few reasons why tomatoes split.

Noted in Gardens Alive, tomato cracking is not an uncommon problem in ripe or near-ripe tomatoes, and the good news is that it's not caused by disease or bugs. Basically, when a tomato splits, this means the outer skin cannot keep up with the pace of growth of the tomato's insides. When there is sudden and rapid growth, splits are even more likely to happen. 

Even when a tomato is ripe or almost ripe, it can and does still take in water (such as after a heavy rainfall), and if the skin is done growing, the inside can still get bigger, and all of a sudden you have weird splits in your tomato. This is even more likely to happen if there wasn't much watering going on prior to the rain shower.

Cracking doesn't tend to happen in tomatoes that aren't yet ripe, simply because the whole package is still growing at a similar pace and the innards aren't yet outpacing the skin. 

If a heavy rain is on the way, and your fruits are almost ripe, go ahead and harvest to let them finish ripening on your kitchen counter. Mulching around the base of your plants will also help, as it can help maintain constant levels of moisture in the soil. 

Some types of tomato cracking, such as what is often found in heirloom varieties that tend to crack near the stem, isn't caused by the same issue — it just kind of goes with the territory of growing big, gorgeous, and tasty 'maters. All you have to do is slice off the top and enjoy.

If you notice your ripening tomatoes are starting to crack, remove them from the vine promptly to avoid bug infestation or rot. Cracked tomatoes are usually still usable — remove the cracked parts, inspect the rest, and use them for your favorite fresh tomato dishes