Why are my tomatoes splitting? How to stop this common problem

Cracking and splitting tomatoes are amongst the most common problems green-thumbed growers face. While this much-loved crop is one of the easiest to grow, some seem to face damage around late summer – following months of varying temperatures and water levels. 

The threat of a splitting tomatoes can feel like enough to deter you from growing tomatoes in the first place, but it shouldn't. While it is hard to guarantee your tomatoes won't split, once you know why it is happening there is a simple trick to help give them the best chance at success, which we reveal below. 

Why are my tomatoes splitting?

According to expert Kate Russell from The Daily Garden, cracking and splitting of tomatoes occurs when the inside of a tomato grows faster than its outside. This can happen for a variety of reasons, including extreme heat, high humidity, heavy rains, and extreme temperature differences between night and day. 

'Irregular watering can also cause blossom end rot, so proper irrigation is always a good idea when growing tomatoes,' she adds. 

How to stop tomatoes splitting

Why do tomatoes split? There are three main reasons, and what you can do about them so that your vegetable garden ideas yield a good crop.

Over-enthusiastic pinching out

Kate Russell warns that removing too many leaves from your plant will encourage tomatoes to split by the end of summer. So, when you're next pinching out tomatoes, it is best to do so with caution. 

Over-watering

Over-watering can cause cracks in the skins, too, so ensure you keep your watering routine to what's recommended, which is daily morning watering early in the season, then twice-daily watering as temperatures increase. Do this with cautious though: tomatoes only need up to two inches of water a week, with container-grown tomatoes needing more than those grown in borders. 

Dry soil

You can use mulch to encourage tomatoes' health further. Cory Tanner, the horticulture program team director at Clemson University recommends adding 'mulch around your plants with a 2- to 3-inch layer of organic mulch (straw, leaves, etc.)'. This will conserve soil moisture. 

'[You can] maintain even soil moisture by irrigating on a regular schedule between rains. Avoid extremes of dry and wet soil,' Cory adds. 

Vegetable growing expert Brett White uses a similar method. However, he suggests opting for red plastic mulch [such as this on Amazon] that is designed to improve your tomato's health. 

'This stops splitting because it reduces the amount of evaporation in the soil that takes place in hot weather, which allows the roots to access water for longer periods of time and in larger quantities,' he explains. 

Will split tomatoes heal?

Horizontal cracks (concentric cracks) are usually mild and often heal; vertical cracks (radial cracks) are often deeper and less likely to heal. In fact, they'll usually get worse. 

Can you eat split tomatoes?

You can eat split tomatoes if there is no fungus, insect or bacterial invasion, which should be obvious to the eye. If you see split tomatoes on your plant, it's usually best to harvest your tomatoes and let them ripen indoors where they can be better protected.