Why Are My Homegrown Tomatoes Splitting?

I picked a huge 1.5-pound Abe Lincoln tomato this year but there several dark cracks around the top. The tomato was fine, tasted incredible, but in the pictures I took to show off, I had it flipped upside down or taken at an angle to hide the cracks. When picking Sungold cherry tomatoes this year to give to take to my parents’ for Sunday lunch, I always ate the split ones before filling up the tupperware with them.

If you know how why those cracks and splits form, you can take measures to reduce the chance of them happening. But believe me, I would rather eat a split homegrown tomato from the garden than a picture perfect grocery store tomato any day of the week.

Are Split Tomatoes Safe to Eat?

Freshly split tomatoes are perfectly safe to eat; the split is purely cosmetic. But if you’ve noticed your tomatoes have suddenly split and you can see the moist flesh inside, pick it right away. It’s an attractive target for pests and will spoil more quickly.

If you have smaller cracks or splits along the top that are white, brown, or black, those are also safe to eat, but you will want to cut away the cracked part. If you notice mold growing in those cracks, cut off the entire top part of the tomato, as you may be able to salvage the rest for eating.

Why Do Tomatoes Split and Crack?

Some tomato cracks will scar over by the time the tomato ripens. Photo by Sheila Sund is licensed under CC BY 2.0.

Tomato splitting is primarily caused by inconsistent watering or a dry spell followed by a heavy rain. Water flows between the tomato fruit and the rest of the plant, so if the plant is under drought stress, water will be pulled out of the tomato fruits. At the same time, when that tomato plant gets several inches of rain, it will quickly start sucking up all that water, some of which will flow back into the fruits. In some cases, the tomato fruits can absorb too much water too quickly, causing it to expand and put too much pressure on the skin, creating a split.

FYI, at the physiological level, the reason for this splitting is due to a lack of calcium (which also can be caused by inconsistent watering) and a thinner skin. Developing fruits can only get calcium that the plant is actively absorbing, so if the soil is dry, the plant can’t take up calcium. Calcium is important for the structure of cell walls, so a lack of calcium means weaker cell walls, meaning they can burst more easily, ergo, cracking.

Some tomato varieties are more vulnerable to splitting, and tomatoes with thicker skins are less likely to split, but any tomato can be affected by splitting.

What Causes My Tomatoes to Split at the Top?

When talking about cracks and splits, there are two types: side/bottom splits and top cracks. Both are due to the water issues discussed above. In the case of top cracks that seem to go around in circles (called concentric cracks), those form more slowly and gradually as the fruit is growing through dry periods. Side and bottom splits are larger and occur more suddenly.

How to Stop Tomatoes from Cracking and Splitting

So, we know that the main issue is due inconsistent water available to tomatoes, causing temporary calcium deficiencies which weaken the cell walls of the tomato, making it more likely to split after heavy rainfall.

Water more frequently to keep your tomatoes from completely drying out. As a rule of thumb, the top 1-2 inches of soil is dry, and I’m not expecting rain, I water my tomatoes deeply (a good inch or two of water). If you’ve planted your tomatoes deep as I always recommend, your tomatoes will be able to tap into the water deep into the subsoil, making them more resilient. to

If your area has hot and dry summers, it’s important to use mulch. Mulch helps keep the soil moist and cool, so it doesn’t dry out from the sun. Mulch combined with deep tomato planting is the best insurance against dry spells. I also recommend mulch for container tomatoes as even a 5-gallon bucket can dry out very quickly with a mature tomato plant growing in it.

It is very unlikely that you simply have a calcium deficiency, but if your tomatoes are already getting plenty of water and you’re using mulch and deep plantings, you can add a calcium fertilizer to your soil or even just crushed/blended egg shells. Egg shells are an excellent source of slow-release calcium. But for almost all of us, the reason for the splitting is water.

What Should I Do If My Tomatoes Have Already Split?

If your tomato has a split, and it’s ripe or almost ripe, pick it right away and plan to eat it within a few days. Split tomatoes are safe to eat, but spoil more quickly and are more attractive to pests, so it’s best to harvest it so you can eat it before the mold and ants come.

If you notice relatively small cracks in your green tomatoes, you can leave them on. The cracks will likely scar over but the rest of the tomato will be fine, but remove any tomato that appears to start rotting on the vine.

Tomato Varieties Resistant to Splitting

Some tomatoes naturally split more than others. My Early Girl tomatoes almost never split, whereas at least a couple of my Sungold cherry tomatoes will always side split after a rain, and Abe Lincolns seem to be born with cracks at the top. Below are some split/crack-resistant varieties.

  • Jet Star F1 (highly recommended)

  • Early Girl F1 (highly recommended)
  •  Pink Girl F1
  •  Mountain Spring F1
  •  Arkansas Traveler
  • Black Cherry
  • Daybreak
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