Why Do Tomatoes Split & Strategies for Preventing It

Ever wondered, “Why do tomatoes split and how can I stop it?” This question is one of the top questions that I get asked, right along with “Why are my tomato plant flowers dropping?”

It is frustrating to see your tomatoes cracking while on the vine. It wastes fruit and causes rot, which can all be very discouraging after the hard work you have put in to grow tomatoes. Let's dive into the four reasons why tomatoes split and what you can do to prevent it!

The Joy of Growing Tomatoes at Home

Growing tomatoes at home is full of joys and challenges. Good growing practices (like proper pruning, watering, and fertilizing) are the best preventative measures to help you overcome these challenges and get a great harvest.

That’s why MIgardener shares top-notch gardening advice available to anyone for free! With these resources, anyone can grow great tomatoes:

• How to Grow Tomatoes: A Complete Organic Growing Guide

• How to Prune Tomato Plants

• How to Stake Tomatoes

• Growing Tomatoes in Containers

• How to Florida Weave Tomatoes

• Troubleshooting Tomato Plant Leaves Curling

• How to Get Rid of Tomato Hornworms

• Tomato Blight (Identification, Prevention and Treatment)

Why Do Tomatoes Split

Cracked tomatoes can happen when tomatoes are just starting to ripen, but it happens more often when you are preparing to harvest them. You’ve probably been there: you have beautiful tomatoes on the vine and decide to leave them just a little longer to achieve perfection, but you come out the next day and, to your chagrin, they have cracked!

To explain why tomatoes split, I like to use water balloons as an analogy. Take two water balloons- fill one up ¼ full of water and one completely full of water.

If you have ever used water balloons, then you already know that the full one is much more likely to pop right in your hand, whereas you might have a hard time breaking the ¼ full balloon, even when you throw it.

It is like that with tomatoes. The tomato skin is like a balloon that is getting stretched thinner and thinner as the tomato expands with moisture. Eventually, it gets to the point of splitting open.

Let’s look at these four causes of tomatoes splitting and how to prevent it from happening:

1. Infrequent or irregular watering

2. Low calcium

3. Not growing crack-resistant varieties

4. Waiting too long to harvest

Infrequent Watering Causes Tomatoes to Crack

The first reason tomatoes split is infrequent watering. Because tomatoes have a thin skin and high moisture content, a sudden burst of moisture can cause them to swell and split.

This rapid moisture absorption may have been caused by a heavy dew during the night, a rain shower, or even heavy watering. But once a tomato splits, it cannot be cured. It will rot quickly and mold, reducing the shelf life.

The solution? To correct this issue, don’t let your tomatoes get bone dry before you water them. Give them frequent, regular water to slowly expand the tomato. This will also reduce your chances of blossom end rot!

The Role of Calcium in Tomato Splitting

Calcium is naturally found in soil. If a tomato plant is not showing signs of blossom end rot, then chances are that you do not have a calcium deficiency. But there doesn’t have to be a deficiency for there to be a benefit!

Adding a few extra percentages of available calcium in your soil can help your tomatoes so much! It will strengthen the leaves, stems, and skins of the fruit. More calcium will ensure that the cell wall that makes up the thin tomato skin is thicker and more elastic, just in case of a sudden burst of water.

So, the second thing you can do to prevent tomatoes from splitting is add a little more calcium. This could come from gypsum, crushed egg shells (although this is very slow-release and not an immediate solution), Trifecta+, or another fertilizer with calcium. Trifecta+ is balanced with gypsum, dolomitic lime, and bone meal, all of which are great sources of calcium!

Selecting Tomato Varieties That Are Crack-Resistant

Split-resistant tomato plant varieties are a little more forgiving. If you are not around your garden as often or have to do more infrequent watering, then planting varieties that are less likely to crack gives you some extra insurance.

Many bush-style determinate tomatoes are crack-resistant, but not all. Do your research to find tomatoes with thicker skins that will be less prone to splitting. Here is a list of crack-resistant tomatoes available from MIgardener:

• Ace 55 Tomato - Having a low acidity, resistance to blossom end rot, and superior drought resistance, this variety is perfect for those who may have been wary of tomatoes in the past. The production is reliable and the size is consistent. It is one of the most common varieties for home gardens to grow because of its delicious flavor. (Semi-Determinate)

• Peace Vine Cherry Tomato - The Peace Vine tomato is a prolific heirloom variety with robust resistance to common diseases and cracking. It is celebrated for its sweet, juicy flavor and abundant yield. This indeterminate plant produces small, round, bright red cherry tomatoes that are perfect for snacking, salads, and garnishes. (Indeterminate)

• Purple Bumble Bee Tomato - A unique purple cherry variety with green marbling. It produces heavy yields all season long that are crack-resistant with fruits 1.5 inches around. The high acidity of this variety makes for a tangy, less sweet flavor. (Indeterminate)

• Wisconsin 55 Tomato - This Wisconsin variety is full of flavor and crack resistance with strong skin and solid red flesh, making it the perfect all-purpose tomato. An easy variety to grow, thanks to its tolerance to so many different climates. (Indeterminate)

• Arkansas Traveler Tomato - An old American classic with rich, true tomato flavor and pink fruit. It is very resistant to cracking, heat, humidity, and drought and is a great producer. (Indeterminate)

• Floradade Tomato - The Floradade tomato is heat-tolerant, developed for hot, humid climates and thrives in temperatures that can cause other varieties to drop blossoms. Known for its resistance to cracking and disease, this hardy plant produces abundant, medium-sized red tomatoes, typically weighing 5–7 ounces, with a classic, balanced flavor perfect for fresh eating, canning, or cooking. (Determinate)

• Roma Tomato - This classic plum-shaped tomato is grown for its massive yields, strong growing habits, drought tolerance, and disease resistance. The Roma Tomato can be used in pasta, spaghetti sauce, salads, and for fresh eating. It is a meatier variety with less juice. (Determinate)

• San Marzano Tomato - The undisputed king of paste tomatoes, gourmet and home chefs seek out the San Marzano for its amazing flavor and perfect texture. Each plant produces insane amounts of medium 3-5 ounce tomatoes. (Semi-determinate)

• Rio Grande Tomato - The Rio Grande is a small slicer tomato that grows up to around 4 oz. It is packed with acidity and sweetness. This variety produces heavy yields on compact plants that will grow all season long. (Semi-determinate)

Smart Tomato Harvesting to Minimize Splitting

The fourth and final way to reduce the chances of your tomatoes cracking is to harvest them a little bit earlier.

I have written down in my garden journal all of the times that my tomatoes have cracked. One thing I realized is that prior to the tomatoes splitting, I noted that my tomatoes were looking beautiful, but I decided to give them just a little more time. That tells me that, when I think tomatoes need just one or two more days, the best time to harvest is actually that day.

Now, don’t pull tomatoes off the plant the moment they blush, as you will lose the vine-ripened flavor and enticing texture. I recommend waiting until the plant ripens the tomatoes to about 75%. At this point, if you leave your tomato on the vine for an extra day or two, it will only change the texture, not the flavor.

When I harvest tomatoes, there might still be a bit of yellow hue left before they turn red completely. But I will harvest that tomato and let it finish ripening on the counter to prevent splitting.

What to Do With Split Tomatoes

You may be wondering if split tomatoes are still good to eat. Yes, they are perfectly safe to eat, but you’ll want to eat them soon because they spoil quickly.

Examine them for signs of rot or mold, then use them just like your other tomatoes. By using split tomatoes, you can reduce food waste and still enjoy the fruits of your labor.

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