Growing tomatoes can be an extremely satisfying experience, and eating home-grown tomatoes is even better! That’s why it’s so frustrating when an otherwise healthy-looking tomato splits.
Tomatoes crack and split due to changes in moisture. While this doesn’t necessarily make a tomato inedible, there are still actions you can take, like consistent watering and early harvesting, that will prevent and limit cracking and splitting.
Types and Causes of Splits
There are two primary types of splits that growers will see in tomatoes:
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- Radial splits
- Concentric splits
Both types of splitting are caused by changes in the moisture level of the soil. When moisture levels change quickly, the tomatoes’ skin splits because it can’t keep up with the tomatoes’ rate of growth (source).
Splitting is especially likely when tomatoes are overwatered after their soil has been left to dry out. The overwatering may be in the form of a heavy rain or over-irrigation. It may also be simply a matter of inconsistent moisture. See What Are The Signs Of Overwatering Plants?
Air temperature effects splitting, as well. An average daily temperature of approximately 75℉ is ideal for tomatoes’ growth and development.
In areas where the temperature exceeds 92℉, tomatoes will not develop their common bright red color; they will be more orange or yellow. This is often mistaken for slow ripening, so fruits are left on the vine longer than necessary. This exposes tomatoes to additional fluctuations in moisture and temperature that can lead to cracks (source).
A radial split is what you see when your tomato splits vertically down its side. This is most common during hot, humid periods.
Unfortunately, once a tomato develops a radial split, your only option is to harvest it, even if it’s not fully ripe. Otherwise, it will rot on the vine before it ripens (source).
Concentric splits are circular and occur around the stem end of the tomato. Depending on your tomatoes’ rate of development, you may see more than one concentric split on the same tomato.
Tomatoes with concentric splits should also be harvested as soon as possible, even if they don’t appear harvest-ready.
Tomatoes with either kind of splitting are still edible, unless they develop a sour odor or begin to ooze. Those are signs of rot, and you should discard your tomatoes at that point (source).
Best Growing Practices for Avoiding Cracks
Variety and Site Selection
If you want to avoid cracks and splits in your next tomato harvest, start by looking for tomato varieties that are crack-resistant. Floralina, Mountain Fresh, Mountain Pride, Mountain Spring, and Sun Leaper are good, crack-resistant options (source).
Choose a planting site that receives full sun and has well-drained soil. Avoid planting too close to trees, shrubs, or other large plants whose roots will compete with your tomatoes for water and nutrients. If you plan to grow tomatoes in a container, make sure there are enough holes in the bottom to allow excess water to drain.
Tomatoes need quite a bit of water, about one to two inches per week. If you live in a zone that doesn’t get that much rainfall per week, you will need to water your tomatoes consistently.
Consistent watering is the key to avoiding cracks and splits! When you water your tomatoes, your goal should be to give them a thorough soaking that will encourage deep root growth.
Tomatoes have root systems that are very efficient at taking in water. In fact, if any portion of the stem comes into close contact with soil, roots will develop!
However, tomatoes’ root system growth may not keep pace with their above-ground growth. If the plant seems to be water-stressed without reason, growers will be tempted to overcorrect by watering more, but it may be that the root system is just small compared to the rest of the plant.
Once it catches up, though, the roots may start carrying too much water to the plant. Again, growers will be tempted to overcorrect and reduce the amount of water given.
These overcorrections, especially if they are compounded by drought or heavy rainfall, increase the likeliness of your tomatoes cracking. As soon as you plant, be as consistent as possible with your watering practices.
There is a widespread belief that tomatoes’ flavor and overall quality is best when they are left on the vine to ripen before harvesting.
However, this is not really true. We have simply become accustomed to equating flavor with vine-ripening, or we have a stronger preference for certain vibrant colors (source).
The truth is that judging your tomatoes’ harvest readiness by their color is risky. Again, in regions with average summertime temperatures above 92℉, tomatoes may not turn red at all. If you wait for a bright, consistent color, your fruit may be overripe before you pick it.
Tomatoes that are harvested before they are fully ripe will continue ripening indoors, if they are picked at the right time. This is all due to tomatoes’ actual ripening process. Understanding this process is another key to avoiding cracks and splits in your tomatoes.
Once a tomato develops a pale green color, it has reached full size. At that point, it begins to produce ethylene gas inside the fruit itself. The ethylene gas sets off the ripening process (source).
Tomatoes reach what is called the “breaker stage” when they are part green and part yellow, orange, or pink. At this point in their development, tomatoes will grow a cell barrier across their stems that block water and nutrients from the vine.
This means that there is no benefit to leaving your tomatoes on the vine once they start to show some color. Since ethylene gas is produced inside the fruit itself, and since ethylene gas is the catalyst to ripening, tomatoes that ripen indoors will be just as flavorful and nutritious as vine-ripened tomatoes.
In fact, the benefits of harvesting tomatoes at the breaker stage outweigh the benefits of leaving your tomatoes on the vine.
First of all, if you harvest tomatoes during the breaker stage, they will have less exposure to fluctuations in air temperature and moisture. This means that you can reduce your tomatoes’ chances of cracking if you harvest early.
Second, early harvesting allows you to sacrifice fewer fruits to squirrels, pests, diseases, and severe weather.
Finally, early harvesting gives you control over the temperature at which your tomatoes ripen. This means that if you live in a warm climate, you can store your tomatoes at a temperature that will allow them to develop a rich, attractive color (source).
Storing Your Tomatoes
Room temperature storage is best for tomatoes that are still in the ripening process. Since 75℉ is ideal for ripening, room temperature is perfect for them to achieve their best flavor and color (source).
Regardless of their level of ripeness, keep your harvested tomatoes out of direct sunlight to prevent uneven ripening.
It’s also recommended to store your tomatoes stem-side up. Tomatoes’ “shoulders,” the bumps near their stem scars, are the most tender part of the fruit. They are more likely to bruise if kept stem-side down.
It’s also possible for you to slow down the ripening process. Simply wrap or cover your tomatoes with paper and keep them in a cool place, between 60-65℉. They will still fully ripen at this temperature, but it may take several weeks (source).
You may be tempted to keep your tomatoes in the refrigerator. However, refrigerators are too cold to keep tomatoes before they are fully ripe. Don’t store breaker stage tomatoes in the refrigerator.
Related Reading: Can Tomatoes Survive Frost? Key Factors To Understand
If cracks and splits have frustrated you in the past and diminished your tomato harvest, don’t be hesitant to grow them again! Consistent watering practices are your best defense against splitting fruit, especially when summer temperatures fluctuate.
Give early harvesting a try as well! Early harvesting is another easy way to protect your crop and have a successful growing season.