Splits in Tomatoes

Most gardeners have experienced the frustration of seeing beautiful tomatoes form, only to develop ugly splits.  Let’s take a look at how this happens and what to do about it.

Black Prince Tomato Showing Split

Why Do Tomatoes Split?

Tomatoes split because something is out of balance in a way that exceeds the fruit’s ability to compensate for it.  Several things can cause this.

1. Shifts in temperature cause things to expand and contract.  Rapid shifts can make the tomato fruit split as the pulp and skin change at different speeds. This can cause deep splits into the core.
2. Irregular watering also causes splits.  The tomato pulp can absorb water, and thus expand, much faster than the skin.  This usually causes shallow splits with just the skin affected, but can go deeper.  It is a particular risk when dry-farming tomatoes without supplemental water.
3. Insufficient nutrients make weaken the growing fruit, causing it to split. This can also cause weak stems or other problems.  Splits may be shallow or deep depending on what nutrients are low.

What To Do About Splits

Tomatoes require a protected environment and steady supplies in order to thrive.  Here are some things you can do to help.

1. Mulch tomatoes to buffer temperature swings.  Red plastic mulch seems to be helpful in preventing splits.  If you expect severe temperature differences, you may also want to throw a floating row cover over your plants.
2. Water tomatoes regularly and deeply.  This makes them less prone to splitting after a heavy rain.
3. Apply compost or other fertilizer in spring before planting and autumn after planting.  Natural fertilizers are more balanced and easy to absorb than chemical ones.  If your plants look hungry during summer, carefully side-dress with extra fertilizer, taking care to keep it away from the stems. Tomatoes feed heavily so keep an eye on this.
4. If your tomatoes do split, examine the fruit carefully.  Ripe or almost-ripe fruits should be picked and used immediately.  Shallow splits on green fruit often heal over.  Medium splits into the pulp might or might not heal, because the splits can allow fungus or bugs into the fruit.  Deep splits into the soft core almost always cause the fruit to rot; you should remove and discard those tomatoes.
5. Some varieties of tomatoes, especially hybrids that grow huge fruits, are more prone to splitting.  Tomatoes with very delicate or very tough skin split more easily too.  Some heirloom/antique cultivars resist splitting by growing modest-sized fruit with resilient skins.  Try growing different varieties of tomatoes to see what works for you.

See also:

• “Cracking and Pouching Resistant Tomatoes”
• “Information On What Causes Tomatoes To Split And How To Prevent Tomato Cracking”
• “Tomato Specialty Variety Seeds”
• “What Causes a Tomato to Crack or Split?”