The time for baskets of beautiful, flavorful heirloom tomatoes is drawing near. If you’re anything like me, you’ve been watching and waiting impatiently for that first flush of vine-ripened heirlooms, anticipating the taste of that sun-warmed globe of fresh goodness. I picked our first few tomatoes yesterday, the Raspberry Lyanna and the Bloody Butcher, and they were everything that was promised and more.
But what a disappointment when you anticipate the bountiful harvest, only to see heavy amounts of cracking in the skin! 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 total loss.
Cracking can occur at all stages of fruit growth, but as fruit mature they become more susceptible, especially as 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 information on heirloom varieties that are more or less prone to cracking, see the heirloom variety chart.
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.
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 and allow access to disease. If the cosmetic look of concentric cracking bothers you, and you grow your own tomatoes, select varieties that the seed catalogs refer to as “smooth” or “perfect”. Sometimes they will note whether the variety is “resistant to cracking” also.
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 they become more susceptible, especially as color develops.
Control of Cracking:
- reducing fluctuations in soil moisture, especially during later stages of development;
- 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).
As the season progresses this year, I will take pictures of developing stages of the heirloom tomatoes. While I am not going to encourage any cracking or disease, if it does occur, I will be sure and come back to this post to update and document. Do you have any photos of cracked tomatoes that you would care to share to illustrate the point? I’d love to share them if you do!
Happy Trails….and may your harvest be crack-free!