Why are my tomatoes cracking and what can I do?

Question

(Memphis, TN. Zone 7)

First garden. I'm growing tomatoes in two parts of the yard. One gets more sun than the other: the partially-shaded area is producing well, but in the the sun-baked area they're cracking before they can fully ripen. Cucumbers, okra and peppers grow fantastically in these same beds, but I suspect the tomatoes are just not getting enough water. I've tried watering the hell out of them, but still, no dice.

Some have tiny spots, as well as cracks.

There are also hundreds of little flying bugs, tiniest things I've ever seen. (Searching this site, they look like whiteflies.) I don't use anything artificial, pesticides, etc. It's possible birds are getting in there, too.

Several tomatoes have actually rotted on the vine and fallen off as mush. :(

The (single) plant is also enormous. Could I simply need to trim/prune it back? I've done zero maintenance and just let it grow wild. Maybe it's just trying to grow too much fruit at once?

The tomatoes in the back yard, partially-shaded, have none of these problems. The plants are also smaller. Those are romas and grape tomatoes, though; I don't remember what kind the problem tomatoes are.

The soil in both areas is a mixture of dirt and compost (chicken & rabbit manure mixed with dried leaves and pine shavings) that had "cooked down" over last fall and winter (with my chickens scratching at it.) It was black gold by the time it went into the beds, so I don't think it's a nutritional deficiency, but maybe?

What can I do? Should I partially shade them? Is it just a bad spot? They're beautiful tomatoes until they crack, I'm so disappointed!

Answer 1

Cracking tomatoes happens when the (almost) ripe fruit expands and the skin can't hold up any more. (A bit like stretch marks...)

There are a few causes that typically lead to different crack patterns, but sometimes it's a bit non-conclusive, so I won't go into detail.

• Excess water, especially after a drought - water as consistantly as possible, protect plants from rain.
• Excess fertilizer late in the season - fertilize early, reduce or stop when fruits start to ripen.
• Temperature differences, especially in fall or when wet fruit are exposed to full sun - consider some kind of a cover, but remember that high humidity leads to fungal diseases, so ensure good ventilation.

A cracked tomato is actually fine for the kitchen - if you pick and use it asap. The wound is an open door for mold spores, as you noticed.

For next season, consider a bit of prior research: There are some breeds that are really prone to cracking, others are labeled "crack resistant" (or whatever the English term is).

Answer 2

The cracks are a physical injury caused by the tomato plant going from too dry to wet too fast. When the plant goes through a sudden change like that the fruit goes from being short on water to suddenly having plenty of water, so it takes in a lot of water very fast and the skin doesn't stretch fast enough to keep up. The skin splits near the top and then the cracks seal up with brown scabs like you are seeing. If it happens on a tomato that is nearly ripe the fruit is perfectly healthy away from the cracks, but has a much shorter shelf life.

The problem is probably more severe on your sun-baked tomato for two reasons. First, more sun means it probably gets drier faster, so it was easier to get dry enough for this to happen. Second, because beefsteak-type tomatoes (which is what the pictured plant is) are more prone to this kind of damage than grape and roma varieties are.

The greener fruit seems to be in good shape. To prevent this from happening again, just keep your watering schedule fairly even from here on out, more if it's hot and dry, less or even none if it's raining a lot.

Answer 3

Cracking in tomatoes is almost always caused by uneven watering. My guess is that the soil in the shady spot of your garden is able to retain water better, so the plants in the shade have more consistent access to water. The soil in the sun is probably drying out more in between watering, so those plants have less consistent access to water. Watering the sunny garden more consistently and possibly mulching the sunny garden will help.

Answer 4

You may have used a lot of Nitrogen fertilizer like Peat, mushroom compost, coffee grounds, or just fertilizer with high N. Nitrogen produces foliage which is needed mostly in the initial stages of growth. Great for green grass. The fruiting plant needs higher Phosphorus for the fruit to grow properly.

If you plant tomatoes like I do where you dig a hole for each plant and lay good soil and fertilizer in it, then you can try to put the high Nitrogen nutrients higher in the hole when the roots are short early in the season and something with Phosphorus lower in the hole. Use chemical fertilizers sparingly. You can alternatively try working some Phosphorus into the soil as soon as they start to bloom. I think bone meal works, it's been a while. Now that I think about it, I believe he did mix high N chemical fertilizer in the top 3 or 4 inches of soil and high P bone meal a little lower down.

There can also be a problem if you have the wrong soil pH for your plants. Google undoubtedly has that answer waiting for you and it's easily tested and fixed. Walmart probably has a kit. However, I'm fairly sure balancing pH takes a fallow season, that is if it's off far enough to cause this type of problem. I suppose you could scrape off some soil and add what you need or make a raised bed if you don't want to lose a season.

When we had confounding issues such as yours, we had access to a great gardening centre that had very knowledgeable employees and we also talked to a local university agriculture extension and even the county agricultural agent for advice, like Mr. Kimble on Green Acres. The county even tested the soil.

One of my Grandfather's secrets was that he collected egg shells and coffee grounds all Winter, throwing it on the soil beds. In the Spring he had me turn the soil, mixing it as good as possible. Then he bought fishing worms and spread them over the area. When the soil started to compact he had me turn it again. He used that soil to make the individual tomato plant holes. Vermiculite was a constant also. Producing a rich, loamy soil with good drainage is key. His plants were not large but they were extremely productive. Being from Tyler, Texas, the Rose Capital (I grew up in Colorado) Grandpa always had some prize roses about. He also had a 13 or 14 foot Sunflower that made the front page with a floret disc three or four times the size of your head.

Answer 5

I'm not really decided on what causes cracking. The consensus seems to be such as uneven watering. I imagine silica, calcium, potassium, nitrogen and temperature might have something to do with it, too. However, I know some varieties are more prone to it than others.

If your tomatoes are Lemon Boy tomatoes, know that that variety is prone to cracking, in my experience. Roma can be, too, though (but not as often); so, I'm guessing you must have different conditions in the other yard with the Roma tomatoes (or else a different strain of Roma than I had). You could try growing the yellow tomatoes in that other yard next time. However, I would recommend just trying another variety, or maybe try to select the cracking out of your tomato over the years (that is to say, never save seed from a cracked tomato, but just the perfect ones).

You might consider the following tomatoes for crack-resistance: Glacier, Dad's Sunset, Siletz, Early Girl or anything from this list. Legend is said to be superior to Siletz, but I haven't heard whether it resists cracking like I've heard Siletz does.

From the aforementioned list, because Lemon Boy is heat tolerant (as far as being able to set fruit in heat goes) and perhaps you live in a hot area, I would recommend checking out these ones particularly: Thessaloniki, Celebrity, Black Cherry, Eva Purple Ball, Pruden's Purple, Gold Nugget, and Yellow Pear. All of those are heat tolerant, except maybe Gold Nugget (but it's parthenocarpic; so, it may set fruit in the heat whether or not it's tolerant; Legend and Siletz are also parthenocarpic).

The only yellow tomatoes I've personally grown to ripeness so far (that I remember by name) are Yellow Pear, Lemon Boy and Galapagos Island, but I should have more to add to that list in future years. I don't recall any cracking problems with Yellow Pear or Galapagos Island, but they're pretty small tomatoes.

Answer 6

I just looked up this problem with my black cherry tomatoes; and there is no consensus. They just started to ripen; and crack. I have soaker hoses that water evenly, so I doubt that is the problem. For now, I am removing them from the vine as soon as they are black/red, even if not quite ripe. My Brandywines are not having this problem; nor are my Romas, which are right next to the black cherries. Could be the extreme heat for a couple days did it, maybe shrinking the skin; and there is no cure for that other than maybe more shade.