Why do tomatoes split?

The grocery store is filled with tomatoes sporting smooth, glossy, blemish-free skin. These types of tomatoes are bred to be uniform. Every stage of their production is controlled and regimented to ensure each fruit is as close to perfect as possible. Plus, any that do happen to split typically get removed before making their way to the produce aisle. In contrast, the tomatoes you grow in your own garden will usually have a more varied appearance. But sometimes those irregularities become damaging, like splits in your tomatoes. When the outer skin cracks, the delicate tomato flesh gets exposed to the elements and usually leads to fast fruit decline. Tomato cracking is common when there are big swings in the amount of water available to plants. A prolonged dry period followed by a deep, soaking rain will cause tomato plants and fruit to grow more rapidly. The tomato skins crack when the flesh expands faster than the skin. Tomato splitting isn’t caused by a pest or disease that will spread to other plants. There is no concern about a plant with cracked tomatoes sharing the problem with nearby plants. If skins crack when the tomatoes are green, the fruit will likely rot before it ripens. If the fruit is showing signs of ripening (turning red, pink, yellow, purple) you can harvest it and salvage much of the fruit, notes Gretchen Voyle of Michigan State University Extension. “All that needs to be done is trim out the damaged areas,” she says. Then, you can use the rest of the tomato in salsas, sauces, or other favorite fresh or cooked recipes.

Tips for Preventing Tomato Splitting

Once tomatoes split, the damage can’t be undone. However, there are a few things you can do to avoid the cracks in the first place.

1. Water Tomato Plants Consistently

Tomatoes grow best with about 1 inch of water a week. If rainfall is less than that, water plants as needed. Deliver water directly to the base of plants using a drip hose or watering wand. Watering plants at the base and keeping leaves dry will help prevent several common foliar diseases.

2. Mulch Around Plants

Spread a 2-inch-thick layer of mulch around the base of tomato plants to help conserve soil moisture. The mulch slows evaporation and helps prevent big swings in soil moisture and skin cracks. Use an organic mulch, such as well-decomposed compost, straw, or grass clippings. At the end of season, either turn any remaining mulch into the soil or leave it in place to continue breaking down beneath a fresh layer of mulch the next season.

3. Grow Split-Resistant Tomatoes

Some tomato varieties are better at tolerating fluctuating amounts of moisture than others. Tomatoes that resist splitting include ‘Celebrity’, ‘Juliet’, ‘Plum Regal’, and ‘Pink Girl’. When shopping for tomatoes, check plant tags for resistance to cracking as well as certain diseases.