One of my tomato plants has leaves curling up on it.

8 Reasons for Tomato Leaves Curling Up in Your Garden

Don’t stress if you find tomato leaves curling up; there are several reasons this might happen to your plant.

I took a walk in my garden last week and noticed that I had a few tomato leaves curling up. I knew immediately that this was more than likely caused by the extremely hot weather we were experiencing – and I might have forgotten to water when we went to the lake.

Oops.

While my tomato plant leaves gradually uncurled and went back to normal with more watering and cooler temperatures, I know that this isn’t always the case. Last year, we had tomato leaves curling up for a different reason – micronutrient deficiency.

If you notice that your tomato leaves are curling upwards, here are a few of the common causes.

Why Are My Tomato Leaves Curling Up? 8 Reasons

When you see the tomato leaf curl, don’t panic. It’s like when you have a bit of a cold or a belly ache. While it could indicate a more serious problem, it’s usually not a big deal and easily remedied.

Make sure you check your garden frequently for signs of a problem. That allows you to take action faster and stop the problem before it kills your plants.

Let’s look at the reasons why your tomato leaves curl up.

1. Environmental Factors

The most common reasons that you notice tomato leaves curling up are due to environmental issues. That might mean that your tomatoes are exposed to too much sun or facing hot temperatures.

Tomato leaves curling up also could be caused by too much wind, adding stress to your plants. If your plants aren’t properly staked and supported, the plants might twist, causing the leaves to curl and die back.

Think of tomato leaves like small solar panels that collect sunlight for the plant. If they receive ample sunlight, the plant forces the plant to curl and close up the leaves to prevent sunburn.

Temperatures are also a problem. If your location faces a heatwave, tomato leaves curl up as a protective measure.

Don’t panic! If this is why your tomato leaves curl up, then as soon as the environmental problems change, you’ll notice the leaves opening and going back to normal.

2. Lack of Water

Another reason that your plants might have leaf curling is that you need to give your plants more water. Tomato plants need ample water; in general, tomato plants need one to two inches of water per week. Container-grown tomato plants need more water than that.

So, if it’s hot outside and you don’t provide enough water (a combination of environmental factors and lack of water), you might see your tomato leaves curling up.

3. Micronutrient Deficiency

If you notice your tomato leaves curling up at the bottom of your plant, the typical reason is that your soil has a micronutrient deficiency. However, most of the time, plants display this with yellowing tomato leaves before any curling happens.

You can fix a micronutrient deficiency in a few ways.

  • Add fresh compost around your tomato plants.
  • Use an all-purpose fertilizer around your plants to amend the soil and get your plants back on track.
  • Consider using Azomite, which is a clay compound full of micronutrients.

4. Curly Top Virus

Take a close look at your tomato plants and see if they’re growing in a wiry pattern with the smaller leaves at the top of the plant curling. This is a sign of a disease called curly top virus.

Curly top virus spreads by the leafhopper pests, and they typically only infect one plant in your garden. That’s great news for you because it means that virus doesn’t spread to other plants.

The bad news is that the curly top virus greatly affects the growth of the infected plant. You can let your plant reach maturity, but don’t leave the plant in the garden over the winter and remove it.

5. Excess Nitrogen

If you add too much nitrogen to your soil, then you might notice leaf curling as well. After the leaves curl, they might become thicker and a dark green color. You’ll notice these symptoms most often on heavily pruned tomato plants.

At this point, don’t apply any more fertilizer to your plant and let the plant use up the nutrients in the soil. Make sure you test your soil next year before adding any more natural nitrogen sources to your garden.

6. Pruning Too Much

Pruning stresses out your tomato plant, but it’s essential for taking care of your plant. The leaves on your plants are how they make food, converting the sunlight into energy. So, if you remove too many leaves, then your plant will struggle.

Over-pruning, especially on a young or poorly established plant, will cause so much stress that it results in curling, yellowing leaves, stunted plant growth, and decrease fruit production.

7. Herbicide Damage

Tomato plants are sensitive to chemical drifts, especially different herbicides. Chemical drifts happen when farms or gardeners near you spray weed control, and it’s carried by the wind, potentially landing in your garden.

When your tomato plants have herbicide damage, the leaves might curl upward or downwards, but they also look twisted and have malformed fruits that you shouldn’t eat.

Watch your plants. Sometimes, the new leaves and branches on the plant might recover, and if they don’t, you should pull the entire plant out of the garden.

8. Pest Damage

If you notice that you have pests on your tomato plants like the tomato pinworms, you might end up with leaf curling. When the pests suck out sap from you tomato leaves, it causes the leaves to curl up and eventually wilt.

Treating this problem relies on you using the proper methods to get rid of the tomato plant pests you have in your garden.

What about Tomato Leaves Curling Down?

What happens if you walk in your garden and notice that your tomato leaves are curling down?

That means your tomato plants have something else happening. Tomato leaves curling down typically indicates that your plants lack nutrients due to root rot.

What is root rot?

Well, this happens when your tomato plants receive too much water either from you or too much rain, and it causes the roots to rot, preventing the plant from up taking more water. Root rot causes the plant’s roots to contract and close, and if the overwatering continues, the roots will shut down entirely, causing the plant to die.

So, what can you do to save your plants?

The best thing is to do stop watering your tomato plants. Wait for the plants to soak up as much as possible. It typically sorts itself out, and in the future, make sure you improve the drainage of your garden beds.

Watch Your Tomato Plants

Growing tomato plants can be tricky, especially if you don’t pay attention to your plants regularly. You never want to miss something like your tomato leaves curling up that could indicate a problem. Thankfully, tomato leaf curl rarely means that your tomato plants are going to die; you can still expect a harvest this summer!

Check out a few other tomato growing articles

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3 Comments

  1. Thank you for the information I thought the tomato plant was dying but now realise I have overwatered them.

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