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Why Do Tomato Leaves Turn Upside Down

Tomatoes are a fantastic crop to grow, but they’re fussy plants. They’re heavy feeders, need just the right amount of water, and they’re prone to a whole host of pests. You may be doing everything right for your tomato plant but still notice their leaves turn upside down. So, what causes this strange phenomenon?

Tomato leaves will turn upside down because of different environmental factors. Overwatering, wind damage, and disease are the most common reasons tomato leaves curl and turn upside down. 

It can be discouraging to see the leaves turning upside down on tomato plants you’ve cared for so carefully. Thankfully, you can avoid this problem by being more vigilant about their care. Read on to learn more about why tomato leaves turn upside down and how you can prevent it.

Why Do Tomato Leaves Turn Upside Down?

Tomato leaves can curl and turn upside down for a variety of reasons. Let’s look at some of the most common causes of this phenomenon and how you can protect your tomato plants.

Water

One of the most common causes of this issue is overwatering. Tomato plants should be getting about 1-2 inches of water per week, and any more than that can oversaturate their soil.

If the soil retains too much water, it can be difficult for your tomato plants to soak up the vital nutrients they need. A lack of calcium is attributed to tomato leaves curling and turning upside down. Their leaves may also become a bit leathery if the plant isn’t getting enough calcium.

Getting the proper nutrients is necessary for your tomato plants to thrive and produce a healthy crop. If you think that your tomato leaves turning upside down is the result of a lack of calcium, you can try adding some additional fertilizer and being more vigilant about the amount of water your plant is getting.

Wind

Wind damage can also cause tomato leaves to turn upside down. Powerful and sustained winds can damage your tomato plants’ leaves and stems, causing them to flip upside down. It can also be a self-defense mechanism for the plant.

Wind can strip plants of their moisture, especially if there’s high heat and low humidity. So the leaves on your tomato plants may curl inwards and flip upside down to protect themselves from losing more water.

This is usually a temporary condition, and your plant will recover once the weather stabilizes. It shouldn’t affect your plant’s ability to produce healthy fruits, although it may cause them to drop fruits early if they were already producing when the strong winds kicked up.

Disease

Tomato plants are susceptible to many diseases and pests. Blossom end rot, early blight, late blight, and geminiviruses are common diseases affecting tomato plants. Those in the geminivirus family are the most likely to cause tomato leaves to curl and turn upside down.

These viruses are most commonly spread by whiteflies, and the only way to prevent these diseases is by tackling the whitefly population. The best way to do that is by spraying your tomato plants with insecticidal soap.

You should spray the soap once a day and focus the spray on the undersides of the leaves where these insects congregate. It’s generally considered best practice to use this spray at night when there’s less chance of it affecting beneficial insects.

Why Are My Tomato Leaves Curling?

Before your tomato leaves turn upside down, you might notice them begin to curl. If you notice your tomato leaves beginning to curl, then you’ll want to figure out why so you can remedy the situation before it progresses.

Many of the factors we’ve already discussed can cause your tomato leaves to curl, including wind stripping away their moisture, under or overwatering, and disease. However, some other factors can cause tomato leaves to curl.

Temperature

Tomato plants need warm weather to thrive, and if they’re exposed to excessive heat or chilly nights, it can damage the plants and cause some leaf curling. Tomatoes need a minimum of 55 degrees F to survive and will thrive in temperatures up to 85 degrees F. Temperatures lower than this can kill your plant. The first sign that they’ve been affected by cold temperatures is leaf curling.

Similarly, excessive heat can negatively affect your plants. Sustained temperatures above 85 degrees F can cause sunburn to your plant. The leaves may develop gray or white splotches and begin curling in on themselves.

It’s best to plant your tomato plants a few weeks after the last frost and protect them with shade if you’re experiencing extremely high temperatures.

Broad Mites

Broad mites are common pests for tomato plants, and they can do serious damage. These tiny pests are only identifiable under a microscope, and they tend to congregate on the bottom of your plant’s leaves.

They prefer to feed on young flowers and leaves. These pests will inject toxins into the plants that they’re living off of, and that toxin will cause your tomato plant’s leaves to curl. The best way to get rid of these mites is by treating your plants with an insecticide.

Herbicide Drift

Many fields and pastures are treated with powerful herbicides that can be carried with the wind. The vapor from herbicides can travel for miles under the right weather conditions, and it can cause delayed growth and leaf curling on your tomato plants.

Herbicides can be found in weed killers for lawns and landscapes, so even if you’re not living next to a treated field or pasture, they could still cause your tomato plant’s leaves to curl. There’s not much you can do to prevent this if the herbicide was used legally on someone else’s property. Your best bet at that point would be to restrict growing your plants indoors or in a greenhouse.

Can Tomatoes Recover From Leaf Curl?

Whether your tomato plant can recover from leaf curl depends on what’s causing it. If environmental factors such as wind, intense heat, or too much sunlight have caused the plant’s leaves to curl, they’ll likely recover once the weather stabilizes.

However, there are some conditions your plant may not be able to recover from. Serious diseases and pest infestations may leave your plant too badly damaged to recover. Nutritional deficiencies can also permanently damage your plant if it isn’t corrected in time.

If only a few of your tomato plants have been affected by leaf curl and you determine that it’s been caused by a disease, you’ll need to remove the infected plants immediately. This will help prevent the virus from spreading to the rest of your crop.

Final Thoughts

Going out to check on your tomato plants and seeing their leaves turned upside down will cause concern among even the most seasoned gardeners. It shows that your plants are under severe stress, and the source of that stress needs to be determined so you can remedy the problem. We’ve outlined some of the most common reasons this happens and how you can prevent it from happening.