Healthy tomato plants result in fresh summer tomatoes grown at home. So if your tomato leaves curl up, you have reason to worry that you won't be able to enjoy a delicious homemade salad made from your favorite vegetables. But here comes the good news! Curling tomato leaves doesn't mean your plants are doomed. There are a number of causes for this, most of which can be treated. In this article you will 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 their leaves upward to protect themselves from water loss. As a preventive measure to prevent this from happening, plant your tomato plants in a windless location to prevent hot, strong drafts from 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. If they are outdoors, they need at least 3 cm of water, whether from rain or watering. Water slowly and deeply so the plants develop deep roots. Mulch the soil around the tomatoes to keep the soil evenly moist.
Problem: Overfertilization with nitrogen
Tomatoes that are oversaturated with nitrogen may have upward curled leaves that are thicker and greener than usual. They may also start producing more leaves, but at the expense of fruit. Too little phosphorus can also cause tomato leaves to curl upwards.
How to fix the problem: Although tomato plants are very nutritious, fertilization should be balanced. After planting in well-fed soil, tomato plants benefit from multiple applications of a balanced fertilizer NPK 5-10-5 throughout the growing season. Avoid fertilizers with a high nitrogen content (first number) or you will have very light green leaves and fewer tomatoes.
- Notice: The most reliable way to determine soil nutrient levels and find out how to correct the imbalance is with a soil test.
You can get care tips on how to properly fertilize tomatoesfind here!
Tomato plants are susceptible to damage from herbicides
Why do tomato leaves curl? If this occurs, it's likely that your plants have come into contact with herbicides - not necessarily through your use. Your neighbors may have sprayed their yard with plant poisons to control weeds and the wind spread them to your plants.
How to fix the problem: Unfortunately, there's not 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 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, in which 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 affected by the disease, it will be difficult to get rid of them.
The second virus is the tomato mosaic virus. It is spread by pests and the use of tobacco products as mulch in the garden. Not only do tomato leaves curl, they become spotty and small, and the infected fruit is brown 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 to separate the infected tomato plants from the healthy ones by cutting out the diseased parts. Under no circumstances should you dispose of them in the trash or compost; instead, burn them. Otherwise they can continue to spread uncontrollably.
Why do tomato leaves curl – Due to mite infestation
When mites feed on young tomato leaves and flowers, they inject toxins into the plant, causing the leaves to twist and become severely deformed. The mites are so tiny that they cannot be seen with the naked eye, only the damage indicates their presence. If the infestation is severe, the underside of leaves and fruits can also turn bronze or rust-colored.
How to fix the problem: You can use a spray based on rapeseed oil. In one liter of water, mix two tablespoons of rapeseed oil, two drops of dishwashing detergent and one teaspoon of denatured alcohol. 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 at intervals of a few days. However, under no circumstances should you treat the plants in direct sunlight as this can cause serious burns.
More tips on how to combat tomato pestscan be found here!
