Have you been blaming birds or insects for splitting and cracking your tomatoes? From my experience, the answer is far less exotic.
Tomatoes crack or split when the inside of the tomato grows faster than the skin can expand.
It is no different than overfilling a balloon with air. The tomato skin is thin and can only hold so much pressure. And if you get the tiniest break, the built-up pressure will cause a larger-sized tear.
So what can cause this rapid growth of the tomato?
Tomatoes split due to irregular watering, where the tomato - often following a dry period - absorbs too much water too quickly. Other common reasons include over-ripeness and leaving mature tomatoes for too long on the vine, forgetting to adjust watering habits during periods of heavy rainfall, extreme temperature fluctuations, and unexpected rapid growth.
Read on to learn how I minimize the problem with split tomatoes in my garden.
But first, did you know that not all splitting and cracking are the same?
What is concentric vs radial cracking
Concentric cracking can be described as the rings that form when you throw a stone into a pool of water.
The circles all have the same center but start small and then grow larger. It’s a bit like a dart board if you like. Concentric splitting is the textbook example of fruits absorbing too much water too fast.
Radial cracking is vertical tears along the side of the fruit. Radial tears are usually deeper than concentric splits or cracks. Some of my Striped Stuffer beefsteaks suffered from radial tears last year. After reading a lot, I concluded that it was due to stress from fluctuations in temperature, and I no longer grow tomatoes in this spot.
One of the main differences between the two splits is the severity or depth of the crack.
Concentric splits are often more shallow and may even self-heal if the fruit is left on the plant.
Radial cracks are deep, and you may as well harvest the fruit. Inspect the fruit closely before you decide to compost or use the fruit.
The main reasons tomatoes split on the vine
Based on my experience, the main culprits are poor watering habits and leaving ripe fruits too long on the plant.
But let’s look closer at the reasons tomatoes split on the vine.
1. Poor watering habits
This is where you should start. Irregular watering is the most likely reason for your tomatoes to crack.
Just think about it, and it will make sense to you.
- Your tomato plants may have been through a period of hot weather and insufficient watering. They are doing their best to survive through this dry spell.
- Suddenly, there is a large influx of water, and the fruits absorb water rapidly.
- The tomato expands due to the absorbed water.
- However, the skin is not flexible enough to expand with the flesh.
- As a result, the skin splits or cracks.
Water your plants regularly to maintain even soil moisture to minimize the risk of split fruit.
2. Leaving ripe fruit on the plant
If inconsistent watering is the main reason, not harvesting mature fruits is a close second.
Tomatoes are more susceptible to split when they are ripe or near reaching full maturity.
Pay close attention to your fruits as they are nearing full ripeness and are sensitive to sudden changes in environmental conditions.
3. Less common reasons leading to cracking and splitting
- Temperature fluctuation and environmental stress: Tomato plants thrive in a stable and predictable growing environment. Anything like extreme temperature changes, strong winds, and even heavy rainfall can stress plants and cause fruits to split.
- Rainfall: Heavy rainfall can lead to excessive access to water and cause the fruit to swell, resulting in cracked skin.
- Unexpected rapid growth: Anything causing a sudden growth spurt in the tomato can lead to cracks. We already covered watering, but adding too many nutrients can have the same effect.
How To Prevent Tomatoes From Splitting
I grow tomatoes in garden beds, containers, pots, and grow bags. And I cannot remember a year when I have not seen at least a handful of tomatoes with splits and cracks.
My point is that it is common. So when I say “prevent,” I really mean “minimize.”
There are several things you can do to create the stable growing environment your tomato plants want and need.
1. Consistent watering
- Whether you water manually or use drip irrigation systems or soaker hoses, maintain even soil moisture.
- Water your plants at the base to avoid getting leaves wet.
- Large established plants have root systems that grow deep. If you do not water deep, your plants will not get enough water.
- Consistent does not mean often. It is better to water less often and deep than to give a little bit of water twice a day.
2. Fertilize according to the recommended dosage
- Never give more than the recommended dose when you fertilize your plants. If anything, give less and observe how your plants react.
3. Mulch your plants
- Add a 5 cm / 2-inch layer of mulch to the base of your plants to retain soil moisture, control weeds, and regulate soil temperature.
4. Harvest tomatoes when they are ripe
I never harvest tomatoes early if I don’t have to.
The one exception is when the growing season ends, and I still have green tomatoes on my plants.
Other than that, tomatoes taste best when they are allowed to ripen on the vine.
But you need to get your timing right. Leaving mature, ripe tomatoes on the plant will inevitably lead to cracking and splitting.
If you are unsure, my best advice is to do the gardener test.
Pick a fruit or two, taste, and decide if you are happy. If you are happy, go ahead and harvest. These are your tomatoes, and no one but you can decide what is right for you.
Ripe tomatoes have a full, deep color and a slight give when gently squeezed.
Can I eat split or cracked tomatoes?
I do, after careful inspection. I have a set of rules that have evolved over time.
I harvest tomatoes with deeper tears or splits when I spot them. If the fruit looks healthy, I use it. If a visual inspection leaves me wondering, I cut the fruit open. If it looks healthy, I use it for sauce or salsa.
But what if the splits are more superficial? It depends on the level of ripeness and the weather.
Even a superficial crack will eventually burst open if the tomato is green and completely unripe. But if the tomato is almost ripe, I often leave it to mature on the plant as long as I do not expect rainfall.
Key takeaways
- Irregular wearing is the most common reason for splitting tomatoes.
- Overripe tomatoes are prone to splitting if left too long on the vine.
- Concentric splits are usually more shallow than radial cracks.
- Inspect split fruits carefully before deciding to compost or eat them.
- Harvest unripe fruits with cracks. They will burst as the tomato grows.
- Consider leaving fruits with shallow splits to ripen on the vine unless rain is forecasted.
- Discarded, cracked fruits go into the compost.
Frequently asked questions
What about blossom end rot?
Blossom end rot is what it sounds like. The flower at the bottom of the fruit rots, leaving you with a soft, dark indentation at the bottom of your tomato fruit.
What types of tomatoes split?
Thinner-skinned tomatoes, like cherry tomatoes, are more susceptible to cracking and splitting.
