Last year I planted a lot of Tomato plants to see which ones I find the best. Sadly, I noticed some of the fruits were cracked; others seem to be okay. How did this happen? I looked into this topic some more, to explain how this came to be and easy ways to prevent it.
Why do tomatoes crack? Splitting indicates an issue with (irregular) watering. Lack of water during dry periods will cause vegetables to crack. Their Skin splits, once water is available again. Furthermore, a lack of nutrients in the soil and high temperatures expedite this problem.
Cracked tomatoes can be eaten, just be quick they won’t keep long
It’s easier to prevent something if you know its cause. Let’s start by looking at the root of the problem in more detail.
The cause of splitting tomatoes
Some good news first: It’s not dangerous. Growing condition is the cause of Splitting, so there is no issue with diseases or pests. One thing to look out for though, Split Tomatoes tend to rot a lot faster, as the crack is a way for bacteria to enter the fruit.
How does this happen? One way Cracks form is during a dry spell. The skin of the tomatoes will create microscopic gaps similar to our skin when it dries out. These small gaps will expand into a crack when water is available again.
Too much water will also cause splits. This time the skin of the tomatoes will not be able to keep up with the pace of the fruit expands.
Temperature is another crucial factor. During Hot days, tomato plants will need lots of water, making it more likely for them to create small splits. Additionally, when temperature fluctuation to widely a different type of crack -called Cat-facing- can form. Low temperatures cause these shortly after trans-planting. If the immature Tomato plant gets damaged (esp. its reproductive parts), it’ll carry this damage down to the fruit. Cat-facing describes corky scars in the tissue of the tomato.
Soil quality and plant placement are also essential for thriving tomatoes. It’s pretty straight forward that without enough nutrients or sunlight, growth will not be optimal. A constant stop’n’go process, during the growing period, will damage the fruit’s skin and lead to splits.
Now we know what causes it, let’s see how to prevent it next.
How to prevent Cracking
Regular Watering: The best method to prevent splitting is to water at regular intervals. Continually supplying your plants with water will prevent microscopic tears. This also prevents growth-surges from happening. I prefer to water my plants deeply once or twice a week. Make sure to check the water level in your soil daily. Tomatoes require ~2in of water a week.
Cracks can still form when it rains a lot. So adopting some other preventive measures can help to reduce damage.
Drainage: To reduce the chance of splitting taking place, ensure your garden bed drains very well. Rain is less of a danger in these conditions because the water will not collect around the roots of your plant. Adding some Stones, Sand, or other materials to the planting spot helps to distribute the water. I recently wrote a whole article dedicated to the bottom layer of raised beds.
Mulching: Adding a layer of organic material to your topsoil will help in many different ways. Mulch stabilizes the soil temperatures, has water-retaining abilities, and over-time releases nutrients. All of which helps to reduce chances for cracks in tomatoes.
Keep your soil healthy: Nutrients play another huge role in preventing cracks from happing. Esp. Calcium is essential in building cell walls. Make sure your plants have all the minerals they need and consider adding some compost or mineral dust (pulverized seashells, for example) if necessary. There are a lot of great ways to help your soil out; I went through some of them in my recent post.
Choose resistant tomatoes: Plants with smaller fruits and thick elastic skin are less likely to split. There are a lot of different varieties to choose from when you want to grow tomatoes without running the risk of cracks happening. Some examples are Big Boy, Chianti Rose, Delicious, Mountain Spring, Red Sun, Sun Sugar. This doesn’t resolve the issue at hand, though, so make sure to improve your watering along with it.
Grow in a greenhouse: Avoiding rain altogether helps to ensure crack-free tomatoes. You still have to keep the soil healthy and water regularly, but don’t run the risk of rain over-watering your plants. I generally stay away from using greenhouses, except for seedlings and immature plants.
There are also a lot of mistakes when growing tomatoes that increase the chances of cracking to occur. These can easily be avoided and help to reduce the number of split tomatoes in your garden.
Mistakes to avoid
Harvest Tomatoes at the right time: Harvest your ripe (or nearly-ripe) tomatoes before rain is coming in. This will reduce the chance of them splitting massively. It’s important to note that they can still crack after harvest, so if you plan on picking your fruits, do so before watering them.
Pick your tomatoes the right way: I find it very helpful to pick my vegetables with the Calyx (the green stem). It makes it a lot easier to handle the fruits carefully. Additionally, the Calyx helps to divert the water, reducing the chance of splitting.
Setting up a watering system: It can be tedious to check the water-level of your soil daily. Installing an automatic watering system is a great way to reduce the amount of time you spend on routine tasks in your garden. This helps to keep your crops watered during dry spells or if you’re on vacation.
Slowly reintroduce water: Be careful when watering plants that did suffer from a drought for a couple of days. They need some time to get used to the average amount of water again. Gradually increase the water you give them for a week until you are back to your usual quantity; This makes sure, that the skin of the tomato can regenerate first before the fruit expands again because of the irrigation.
Protect immature plants: Young plants can suffer permanent damage when exposed to cold temperatures. Prepare your plants for low temperatures (<60°F -16°C-) by wrapping them in an insulated plant cover. Esp. when dealing with catfacing Tomatoes, this can help to reduce the amount of damage done to your crops.
What to do after your tomatoes split
Move your plants into the sun: If your plants are mobile, consider placing them in a spot with 8-10 hours of sunlight. This will help to reduce the chance for mildew and other fungi/bacteria based infections. The splits in the tomato is an excellent way for unwanted guests to enter and replicate.
Pick them: It’s probably best to simply pick any cracked tomato. They will keep ripening even after the harvest. To speed up the process, put them in a cardboard box in a warm room. Place a ripe banana with them (ripening fruit release ethylene – this gas helps to speed up the process). Sunlight isn’t necessary for the after-ripening, but make sure you don’t stack them on top of another.
Why Tomatoes are prone to cracking
How about other Vegetables? Cracking is not a tomato-exclusive-phenomenon. Every fruit can have issues with splitting. Some plants are better at adjusting to unstable watering conditions and temperature. A very flexible, thick skin helps to reduce the chance of cracking too.
And here lies the crux, Tomatoes have a fragile, thin outer layer. This makes them vulnerable. Larger tomatoes are more sensitive to weather conditions and more prone to crack. Cracking is an indicator of the health of your plants. Make sure to check how your crops are doing!
Can you eat split tomatoes? Yes, cracked fruits are perfectly edible. The only thing to keep in mind: Split vegetables rot faster than normal ones.
Why do Tomatoes split after harvest? There are a couple of possibilities here. It’s most likely that they already had small cracks, and by picking them, they just became visible. Even when collected very carefully, they might split. The fruit can still pick up water after harvest; sometimes, the skin can’t handle the internal pressure and cracks. To prevent it, pick your tomatoes with the Calyx (the green stuff) and gently place them in a basket. Make sure only to wash before you eat them.