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Why Do Tomatoes Crack? (Plus 4 Easy Ways to Prevent It)

Why Do Tomatoes Crack? (Plus 4 Easy Ways to Prevent It)
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Who doesn’t love a lovely juicy tomato, freshly picked from your own back yard? The gardeners who find their tomatoes are cracked, have darkened skins and HAVE much less juice, that’s who.

It leaves them pondering the question of why do tomatoes crack? And the answer is fairly simple.

It’s an irregularity in their watering frequency.

Gardening advice for tomato growing is to supply the plants with one to three inches of water per week. Where things go off-track is accounting for the weather.

A few inches of water per week on tomato crops is fine for tomato plants grown in a greenhouse or indoors. For crops planted in ground soil, that few inches of water has to account for rainfall too.

Naturally, a heavy downpour can see your tomato crop drenched in one afternoon. The excessive water causes the skin on the tomatoes to crack.

Think of the outer skin on the tomato similar to water balloon. It can only take so much pressure before it eventually ruptures.

With a tomato, the structure is similar. The moisture builds up inside the tomato, but as the juice is thicker than water, when the tomato cracks, it releases oxygen and some moisture.

All that’s happening when a tomato splits is the skin ruptures to eliminate excess oxygen and moisture. It can’t do anything else but crack.

When you notice a split tomato for the first time, or if it keeps happening, it’s natural to wonder if they’re edible. Obviously, that will be why you’re growing them.

Is it Safe to Eat a Split Tomato?

Sometimes! Split tomatoes can be safe to eat, but you should always inspect the fruit for signs of any infection.

As the skin on the tomato is ruptured, it opens up an entry point for bacteria and fungi. The longer a cracked tomato is left on the vine, the higher the likelihood that something’s going to ruin it.

The worst are fruit flies as those will take advantage of any splits on tomato plants and can infest the whole crop.

Best practice with split tomatoes is to pick them, wash them, inspect them and cut the skin from the effected part of the tomato. Tomato plants that are cracked need to be served sliced.

It’s never advisable to eat a split tomato like you would an apple. You can do that with a healthy ripened tomato, and they should do taste delicious, but the flavor will be effected on the split parts of the skin, which is why it’s best to cut around the split, then serve it sliced.

How to Prevent Tomato Splitting

Greenhouse grown tomatoes or tomatoes grown indoors are relatively easy to prevent cracking as it’s caused by excessive watering. Simply adjust your watering frequency to give the plant only what it needs. A maximum of 3-inches of water per week.

For tomato plants grown outdoors, that’s going to take some more corrective measures to prevent tomatoes from cracking in the future.

A Few Tips to Prevent Tomatoes from Cracking in Outdoor Growing Conditions

1 – Mulch the soil with Red Tomato Plant Mulch

Technically, this isn’t a mulch at all. It’s red plastic sheeting and it’s much thinner than any landscaping fabric, so it won’t do anything for weed control. What it does is reflect far-red light which interacts with the phytochromes in tomato plants.

It essentially regulates the plants growth and has shown to boost the size of tomatoes by up to 20%.

Naturally, the larger a tomato you can grow, the more moisture it can hold and given it’s too much moisture that causes tomatoes to crack, by growing bigger tomatoes you can prevent the splitting problem.

2 – For Outdoor Crops – Plant Tomato Varieties that are Crack Resistant

Some types of tomatoes are more crack resistant than others.

Examples of species considered crack resistant include: The Arkansas Traveler, Big Boy, Big Beef, Black Cherry, Burpees Big Girl, Burgess Crack Proof, Chianti Rose, and Blondkopfchen, to name a few…

You can find an entire list of crack-resistant tomato plant varieties on Harvesttotable.com.

3 – Check Your Soil Conditions to Make Sure it’s Retaining Moisture

The ideal soil type for growing tomatoes is a rich and fertile soil or a peat-free potting soil. Both types are better equipped to maintain a consistent moisture level, ensuring there’s a regular supply of nutrients reaching the plant.

When you inspect your soil, check to a depth of 4-inches to ensure there is adequate moisture retention. If the soil isn’t retaining moisture to a depth of 4-inches, there are ways to improve your soil fertility.

Among the most effect methods to adapt ground soil so it retains more water is to add in some sphagnum peat moss, which can hold up to 20-times its weight. This can be tilled into your soil to a depth of six to twelve inches.

These are suitable as longer-term solutions, however, a quicker and easier fix is to amend the soil with organic materials you likely already have access to. These can include grass clippings too as those are a rich source of nitrogen.

Another reason you need to pay attention to the soil moisture is because when it becomes too dry, you can wind up with a crop of tomatoes suffering from blossom end rot, which is little black spots that appear on your tomatoes.

Soil that’s too dry can either cause the skin on a tomato to split, or the bottom of it can be have signs of blossom end rot. Neither are good, which is why you should periodically check your soil moisture level and amend it if it’s not holding water.

4 – Pick Your Tomatoes Before they are Fully Ripe

Every tomato grower is guilty of thinking they’ll leave a ripened tomato for just one more day. The truth is, tomatoes often ripen better indoors anyway so it’s really not worth the risk of leaving it on the vine trying to get it to the perfect color.

In fact, leaving it on the vine is likely to attract birds and for cracking, the worst offenders are cherry tomatoes. Definitely pick cherry tomatoes before they fully ripen.

If you’ve tried this before and found your tomatoes wrinkling, which can be just as bad of a defect as a cracked tomato, there’s a simple trick to ripen tomatoes indoors, at room temperate that prevents wrinkling. It’s by sitting them on a flat surface, stem side down.

This way, the tiny holes from where the tomato was attached to the vine are still sealed so there’s nowhere for excess juices to escape and being indoors, excess water won’t cause the skin to split.

You can pick tomatoes as soon as they start to change color from green. Common colors for most tomato species in the early stage of ripening are yellow, orange, pink and light-red.

When they change to those colors, you can pick them, bring them indoors and store them at temperatures from 70oF to 75oF. Anything cooler than 70oF when the tomato is off the vine will slow the ripening process so keep them out of the refrigerator until they’re ripe.

Whether the tomato ripens on or off the vine has little to no effect on the taste or texture, which is why it’s better to pick tomatoes early, avoiding the risk of a downpour ruining the tomatoes you’ve patiently waited to fully blossom and ripen.