If you grow tomatoes, chances are you've watched your beautiful harvest ripen, only to look one morning to see that tomato you've been eyeing for your BLT suddenly split. While tomatoes can split at any stage—green or ripe—it seems most frustrating when you're ready to harvest that delicious fruit for a tasty meal. How can you prevent tomatoes from splitting? And, most importantly, can you still eat the fruit?
Why Tomatoes Split
Tomatoes split due to fluctuations in the amount of water they receive. When tomatoes grow in drought conditions or have little supplemental water, a heavy rain can cause the insides of the tomatoes to grow faster than the outer skin, resulting in the tomatoes cracking. Cracking can occur at any stage—green or ripe—but it seems most frustrating when you're ready to harvest a rich, ripe tomato for a meal.
Tomatoes may crack in two different manners: vertical splits, where radial cracking extends from the top of the fruit to the bottom; and concentric cracking, which often appears on the top of the fruit, forming cracks around the stem on large, heirloom beefsteak varieties. While both forms of cracking may allow pests to enter the fruit or promote rot, concentric cracking sometimes is not severe. If the cracking doesn't expose the interior of the fruit, you can allow it to remain on the vine to ripen, but keep an eye on it.
How to Prevent Tomatoes from Splitting
You can't always prevent tomato splitting; a downpour that dumps several inches of rain on your garden in a few hours may result in split tomatoes no matter what you do. But you can make it less likely that your tomatoes will split by doing the following:
- Water Regularly and Deeply. Tomatoes need about an inch of water per week, so water your tomato plants every two to three days during the summer. (You can tell if your plant needs water by sticking your index finger an inch into the soil at the base of the plant. If it's moist, no need to water. If it's dry, time to give the babies a drink!) When you water, target the base of the plant and avoid splashing soil on the leaves to prevent the spread of soil-borne diseases like blight and septoria leaf spot. Water deeply. Even better, use drip irrigation. Regular, deep watering will minimize the impact of a sudden rainstorm, because your plants won't suffer the shock of excessive water after ongoing dry conditions, which causes fruit to split.
- Mulch. Provide your plants with a two- to three-inch layer of organic mulch, such as straw, pine needles, or shredded bark. Mulch helps maintain consistent soil moisture levels, and you'll deal with less splitting.
- Look for Resistant Varieties. Check the plant's label or seed catalog for varieties that resist splitting. Many hybrid varieties offer not only disease resistance and high productivity, but they also are less prone to split.
- Pick Tomatoes Early. Your tomatoes are almost ripe, and you're expecting a major rainstorm. Now is the perfect time to pick your tomatoes before they're overwhelmed by extra moisture. Tomatoes that have begun to change color will ripen on or off the vine, so harvest them prior to a storm and place on a windowsill to complete the ripening process. (A side benefit for early harvest: less chance of pests eating your fruit!)
- Provide Good Drainage. Planting your tomatoes in raised beds or containers with drainage holes offers the best drainage for your plants if they experience a deluge. Both raised beds and containers drain well--just make sure to use good, loose soil that doesn't compact. Because nutrients leech out of containers as the water drains, make sure to feed them with an organic fertilizer according to the directions on the label.
What to Do if Your Tomatoes Split
If your tomatoes do split, it's important to harvest them as quickly as possible. Split tomatoes are much more susceptible to rot and insect damage.
While you may not be able to completely avoid splitting, don't worry--you can still eat the tomatoes! Inspect them carefully for any signs of insects or rot, and toss any fruit that smells sours or oozes. Then, create your favorite dish with your garden treats! They won't store long, so be sure to eat or cook with them right away to enjoy your garden efforts.
What Causes Tomatoes to Crack. North Carolina Cooperative Extension