Cracked tomatoes are one of the most frustrating problems for heirloom tomato growers. You wait weeks for that perfect fruit, and then it splits on the vine. I used to see this every season at HeathGlen Organic Farm, especially with thin-skinned heirloom varieties.
There are two types of cracking: concentric (rings around the stem) and longitudinal (splits from top to bottom). One is genetic and cosmetic. The other is caused by inconsistent watering and can ruin fruit. Both are manageable once you understand what’s happening.
Quick Summary: Tomato cracking comes in two forms. Concentric cracking (rings around the stem) is genetic and cosmetic. Longitudinal cracking (vertical splits) happens when the fruit absorbs water faster than the skin can expand, usually from inconsistent watering. Prevent radial cracking by maintaining consistent soil moisture, keeping good foliage cover, and selecting crack-resistant varieties. Read time: 5 min | Experience level: Beginner
Jump to: Concentric Cracking | Longitudinal Cracking | Preventing Cracking | FAQ
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Why Do Heirloom Tomatoes Crack More Than Hybrids?
Cracked tomatoes are a common problem for heirloom tomato growers.
Sometimes the cracking will just mean a shorter time on the counter before you eat it, but deeper cracking can also allow disease to enter the tomatoes and result in significant losses.
Cracking can occur at all stages of fruit growth, but as fruits mature they become more susceptible, especially as their color develops.
Some varieties of tomatoes are more susceptible to cracking than others, regardless of whether it is an heirloom variety or a hybrid variety.
For detailed information on heirloom varieties that are less prone to cracking, see the heirloom variety charts.
There are two different forms of cracking in tomatoes, one of which is primarily cosmetic and one which is a result of weather and growing conditions.
What Is Concentric Cracking?
Concentric cracking occurs in a ring or rings around the stem end. This is a genetic characteristic and can’t really be prevented.
The good news is that there is absolutely nothing wrong with the fruit, and the taste is fine. Scar tissue forms over the cracks, preventing access to bacteria and fungi, which would result in rotting.
Occasionally, with heavy rains the scar tissue may open up resulting in some rotting. This is no longer just cosmetic and you will want to harvest those tomatoes and cut off the portion with open cracking.
If the cosmetic look of “non-open” concentric cracking bothers you, and you grow your own tomatoes, select varieties that the seed catalogs refer to as “smooth” or “perfect”.
Sometimes, but not always, they will note whether the variety is “resistant to cracking”.
What Is Longitudinal (Radial) Cracking?
Any tomato variety can develop longitudinal cracking, where the tomato splits from top to bottom. Longitudinal cracking (also referred to as radial cracking) starts at the stem end and progresses toward the blossom end.
This type of cracking happens when the internal expansion in the tomato is faster than the expansion of the “epidermis”, forcing the skin to crack to accomodate the expansion.
Essentially the skin on a more mature tomato can’t expand anymore in response to the absorption of water, so the skin splits open.
Don’t be afraid to eat these split tomatoes, or use in cooking, as long as you harvest them before bacteria and fungi contaminate the split.
Cracking can occur at all stages of fruit growth, but as fruit mature and become larger they become more susceptible, especially as color develops.
How Do You Prevent Tomato Cracking?
With respect to concentric cracking, the only thing you can do is select varieties that do not exhibit this genetic characteristic. That means reading good seed catalogs carefully and looking for phrases such as “smooth tomatoes”, ”perfect tomatoes” or “resistant to cracking”.
For radial cracking, prevention is achieved by:
- reducing fluctuations in soil moisture, especially during later stages of development. Make sure you don’t let the plants dry out and then deluge them with water. Keep the watering nice and consistent. A good rule of thumb is to poke your finger in the soil and when it is dry down to 1 inch, it’s time to water.
- selecting crack-resistant varieties;
- maintaining a good foliage cover, since exposed fruit are more susceptible;
- harvesting your tomatoes at an earlier stage of development (of course, this results in less of the sugars and complexity of flavors developing).
More on Heirloom Tomato Varieties
- How to get the earliest tomatoes
- Which heirloom tomatoes have the most flavor
- Best heirloom tomato varieties trialed in 2020
- Growing tomatoes in pots
- Try this smoked tomato jam for a Winter treat
FAQ
Yes, if you harvest them promptly. Shallow cracks with healed scar tissue are fine. Deep cracks that expose flesh can let in bacteria and fungi. Cut away damaged portions and use the rest.
Longitudinal cracking happens when the inside of the tomato expands faster than the skin, usually from sudden water uptake after dry conditions. Concentric cracking is genetic.
Generally yes, because they have thinner skins than hybrids bred for shipping. But crack-resistant heirloom varieties exist. Check seed catalog descriptions.
Maintain consistent soil moisture. Don’t let plants dry out and then flood them. Mulch to regulate moisture. Keep foliage intact to shade fruit. Harvest slightly early in rainy weather.
Look for varieties described as “smooth,” “perfect,” or “crack-resistant” in seed catalogs. Carmello, Thessaloniki, and Green Zebra are known for crack resistance.
Yes. Mulch regulates soil moisture, preventing the dry-wet swings that cause radial cracking. Apply 2-3 inches around plants.
Unfortunately I have many examples of tomatoes cracking. If you would like a picture I can e-mail one. Just send the address.
Hi Pattie, I’m so sorry about your cracking problems. Some tomatoes are more prone to it than others, and knowing what the perfect watering regime is doesn’t necessarily mean it’s easy to pull off. I had some cracking problems early on this year so (unfortunately) I got some pretty informative photos. Thank you for the offer though. Good luck with the rest of the season!
My cracking occurred in circles around the top of the tomatoes. What kind of cracking is this and is it safe to eat?
I have Cherokee purple tomatoes, cracking on top.
Yes, a lot of the large heirloom tomatoes will crack on top. It’s because heirloom tomatoes have thin skins. When tomatoes were hybridized, they were hybridized to ship well (hence thick skins). The problem was they now had thick skins and lasted longer on the grocery shelves but a lot of flavor was hybridized out of them.
Some varieties of heirloom tomatoes don’t crack as much. Go for the medium to small ones like Thessaloniki for red varieties, Carbon for the black varieties, Kelloggs for the Orange varieties and Hughes for the pale yellow varieties. There are other ones that don’t crack as much as Cherokee purple. Just read the descriptions when ordering and it will usually say something like smooth or crack-free.
It’s happening when very small and green. I’ve got them in large containers and watering 2x/day. They are Cherokee Purple.
My guess is that you are watering too much. Heirlooms (especially the big ones like Cherokee Purple) have very thin skin which can lead to cracking. You should be able to stick your finger down in the soil and if it is dry down an inch it is time to water. Overwatering or inconsistent watering in pots can cause problems (like blossom end rot). It’s harder to grow the large tomatoes in pots so if you have any garden space try that next year and stick with hybrids or small to medium tomatoes in pots.
Hi my heirloom tomatoes are cracking at the top and the cracks are black. Can you tell me about this? Can I carve it out and use the rest?
Yes, you can carve it out and use the rest. Some varieties of heirlooms crack more often than others, but most of the time it is fine. Just don’t use it if the cracks are deep and it’s black all the way through. Also, try and have the watering be as even as possible so the don’t get dry and then are deluged with water. Heirlooms have very thin skins and crack easily.
It might be too late, but this post helps understand and prevent cracking: https://farmtojar.com/how-to-reduce-cracking-problems-in-heirloom-tomatoes/
yes i have photos id like to share .
Are you able to upload them to the comment section?