Healthy tomato plants result in fresh summer tomatoes that are grown at home. So if your tomato leaves are curling up, worry that you won’t be able to enjoy a delicious homemade salad made with your favorite veggies. But here comes the good news! Curling tomato leaves don’t mean your plants are doomed. There are a number of causes for this, most of which can be treated. In this article, you’ll learn why tomato leaves curl and how to combat the problem!
Why Do Tomato Leaves Curl – Heat, Drought and Wind
In very hot, dry, or windy weather, tomato plants curl up their leaves to protect themselves from water loss. As a preventative measure to prevent this from happening, plant your tomato plants in a windless spot to avoid hot, strong drafts reaching your plants. It is also important that they get some shade in the late afternoon.
Another important step in caring for tomatoes is to always water them well. When placed outdoors they need at least 3 inches of water, whether from rain or watering. Water slowly and deeply to help plants develop deep roots. Mulch the soil around the tomatoes to keep the soil evenly moist.
Problem: over-fertilization with nitrogen
Tomatoes that are oversaturated with nitrogen can exhibit upward curled leaves that are thicker and greener than usual. You can also start producing more leaves, but at the expense of fruit. Too little phosphorus can also cause tomato leaves to curl up.
How to fix the problem: Although tomato plants are very nutritious, fertilization should be balanced. After planting in a well-nourished soil, the tomato plants will benefit from repeated applications of a balanced fertilizer NPK 5-10-5 during the growing season. Avoid fertilizers with a high nitrogen content (first number), otherwise you will have very light green leaves and fewer tomatoes.
- Notice: The most reliable way to determine the nutrient content of the soil and to find out how to correct the imbalance is a soil test.
Care tips on how to properly fertilize tomatoes can be found here!
Tomato plants are susceptible to damage from herbicides
Why do tomato leaves curl? If this happens, chances are your plants have been exposed to herbicides – not necessarily through your use. Your neighbors may have sprayed their garden with plant toxins to control weeds and the wind carried them to your plants.
How to fix the problem: Unfortunately, there isn’t much you can do in this case. Depending on the extent of the damage, the affected plant may regenerate on its own and the new growth may appear normal.
However, if the new growth continues to show signs of damage, you will need to remove and replant the plants.
Tomato leaves turn yellow because of viruses
There are two common viruses that cause leaf discoloration in tomatoes. The first is tomato yellow leaf curl, which is when the tomato leaves turn yellow. This virus is spread by whiteflies. As a preventive measure, you can spray the plants with neem oil once or twice a week to prevent whiteflies from getting near the plants. However, if your tomatoes are already infected with the disease, it will be difficult to get rid of them.
The second virus is the tomato mosaic virus. It is transmitted by pests and the use of tobacco products as mulch in the garden. Tomato leaves not only curl, they also become blotchy and small, and the infected fruit is brown on the inside. The virus is dangerous throughout the growing season.
Once the tomato plant is infected, there is no treatment option. The only thing you can do is separate the infected from the healthy tomato plants by cutting out the diseased parts. Don’t dispose of them in the trash or compost, but burn them. Otherwise, they can continue to spread uncontrollably.
Why do tomato leaves curl – Due to a mite infestation
When mites feed on young tomato leaves and flowers, they inject toxins into the plant that cause the leaves to twist and severely deform. The mites are so tiny that they cannot be seen with the naked eye, only the damage indicates their presence. Severe infestations can also cause the undersides of leaves and fruit to turn bronze or rusty.
How to fix the problem: You can use a spray based on rapeseed oil. Mix two tablespoons of canola oil, two drops of dishwashing liquid and one teaspoon of denatured alcohol in one liter of water. Then wipe the infected parts of the tomato plant with it. Leave the mixture on for a few hours and rinse thoroughly with clean water. Repeat the process several times a few days apart. However, under no circumstances should you treat the plants in the blazing sun, as this can cause severe burns.
For more tips on fighting tomato pests, click here!