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Why Do Tomatoes Split and Crack? (Overcoming and Preventing It)

From his early days, Brandon helped his grandmother in her garden. He has always been passionate about tomatoes.

A severely split cherry tomato.

A severely split cherry tomato.

Why Are My Tomatoes Cracking and Splitting?

It is not unusual to come across some problem or another when growing produce in your garden. Tomatoes are no different. The most common problem when growing tomatoes is that of them cracking and splitting on the vine just as they are about to ripen.

It is very disheartening and frustrating to watch this happen literally overnight after months of hard work and a few weeks of excitement as you watched your tomatoes grow. It's not all bad news though. You'll be glad to know that neither cracking nor completely splitting tomatoes are caused by pests or disease, and you can therefore easily prevent it.

Why It Happens and What You Should Do

This is why it happens: Tomatoes begin to crack when the skin of the fruit does not grow quickly enough to support the growth of the flesh within.

Immediate action plan: Harvest any tomatoes that have split and eat them as soon as possible because they won't stay edible for long once cracked open and harvested. Leaving them on the plant is an option, albeit a risky one, as it is going to be more susceptible to parasites, and in extreme cases, it would begin to rot.

This isn't a problem you would typically notice on green tomatoes because the skin is still growing and the skin is a lot stronger and less susceptible to break open. This is why it is very unlikely that you would lose tomatoes to cracks.

Some Heirloom Tomatoes Crack on Top—This Is Expected

It is important to know your tomato. Some heirloom tomatoes tend to crack near the top as they grow. This is expected in some varieties, beefsteak tomatoes for instance. This also tends to happen in the case of the Cherokee purple, as seen in the image below. It definitely isn't wise to harvest in this case.

I must add that many large varieties of heirloom tomatoes do not ripen all the way to the top. The longer you wait, the more the flavor changes moving away from the ideal. Some varieties are ready to be harvested when the top is still a bit green shouldered.

A cracked Cherokee purple heirloom tomato on the vine.

A cracked Cherokee purple heirloom tomato on the vine.

What Causes Tomatoes to Split on the Vine?

We have already seen that tomatoes crack when the growth of the flesh outpaces the growth of the skin. This brings us to the next question—what causes this to happen?

Your tomato is not really "growing" when this occurs. There is no massive cell multiplication happening. Instead, the cells of the fruit are just absorbing more water than the typical quantity they hold, which causes them all to bloat simultaneously, thereby giving a false impression that the fruit has suddenly grown.

This tends to happen when there is a sudden influx of water to the soil. There are two instances where this happens, one natural and the other human error.

  • A sudden and heavy rainfall soaking the soil.
  • Irregular watering where the soil goes from dry to soaking up a lot of water.

In both instances, the soil needs to hold this sudden influx of water for a sufficient period of time. Anything above a quarter of an hour could begin to cause problems if I were to make an educated guess. Therefore, your regular practice of watering every time your soil goes dry should not cause the fruit to crack. It is very important that you follow the right watering techniques throughout the season, but this is all the more important during the fruiting phase if you want to prevent cracks and splits.

A split tomato that left on the vine that shows signs of the split healing up. Pathogens if any would have already infected the fruit, it is wise to harvest this tomato and not to continue leaving it on the plant.

A split tomato that left on the vine that shows signs of the split healing up. Pathogens if any would have already infected the fruit, it is wise to harvest this tomato and not to continue leaving it on the plant.

How to Prevent Tomatoes From Splitting

You may not always get through a season without any split tomatoes, but there are plenty of things that you could do to prevent or lower the chances of your tomatoes splitting.

Pick Your Tomatoes Early and Often

Every single one of us has looked at a ripening tomato and decided to leave it on the vine for a few more days so that it could ripen even more. Even though this may seem like a brilliant idea, it's not always the best. Tomatoes ripen really well if harvested the moment they begin to turn red. Do not pluck, but cut them off just above the calyx.

If you are expecting rainfall, you should definitely go out into your garden and pluck any fruit that shows signs of ripening, because a combination of ripening fruit and rainfall drastically increases the probability of the tomatoes splitting open.

Water on Schedule

If your plants are fruiting it is a good sign that you have been taking care of them well enough and you should continue watering them on the same schedule. However, if you've been watering in a non-optimal way, you may not know until the first batch of tomatoes begins to ripen. You should definitely master the art of watering before you reach this point. I have written an exhaustive guide on watering tomatoes that you may find helpful.

Mulch Your Plants

The only way to prevent your fruit from cracking up is to prevent an influx of water reaching the fruit. A good way to do this is to mulch your tomato plants. Doing this regulates moisture levels in the soil and the plant always has access to water. Due to this constant access, the flesh and skin both grow together right from when the fruit is young until it begins to ripen while at the same time the soil is not soaked thereby preventing root rot and many other issues. You could use any kind of mulch. Coconut husk is my favorite, but you could use dried leaves from your garden, wood chips, straw, and even plastic.

Plant on Raised Beds or Ridges

If your area is prone to heavy rainfall around harvest time it is wise to plant your tomatoes on raised beds or on ridges. This prevents them from being completely drowned in water in case of a heavy downpour. Other drainage methods would work too.

Calcium Is Essential

It is always important to fertilize your tomato plants with the right nutrients. When it comes to splitting tomatoes, the nutrient of importance is Calcium. It is transported through the xylem tissue and it is therefore not possible for the plant to move around calcium from other parts of the plant to the fruit. The only way for it to get to the fruit and any other new growth is if the nutrient is taken directly from the soil along with the water uptake.

Calcium is essential because it helps in strengthening the cell wall of plant cells. A lack of calcium can also lead to other serious issues such as blossom end rot. My guide on fertilizing tomatoes explains the types of nutrients the plant needs at different stages of its growth.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.


Brandon Lobo (author) on July 02, 2020:

Hi Susan, I'm not really sure. I have not tried this before. You can in principle do it, but it may end up being too strong of a dose and as you would have read, too much can lead to problems of its own. Maybe just a little bit?

Susan on July 02, 2020:

Can I soak calcium tablets in water overnight and use the water for my tomatoes plants.

Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on April 27, 2020:

Brando Lobo, yes, I'll do. Thanks for responding.

Brandon Lobo (author) on April 27, 2020:

Thanks for the comment Miebakagh, hopefully, you plant them again someday.

Miebakagh Fiberesima from Port Harcourt, Rivers State, NIGERIA. on April 27, 2020:

Brandon Lobo, I plant tomatoes when I was 13-yeas. I do not farm again. But hopefully some other day I will. Thans for sharing insights about tomatoe challenges.

Brandon Lobo (author) on April 26, 2020:

Hi Liz, thanks for reading and the comment. Take care.

Liz Westwood from UK on April 26, 2020:

I have noticed this before, when looking at tomato plants. This excellent article clearly explains the causes and comes up with easy to apply solutions to the problem.