September 9, 2025, 4:11 am | Read time: 3 minutes
Tomatoes are among the most popular vegetable plants in home gardens or on balconies–even though they are anything but easy to care for. These demanding plants quickly show when something is amiss. A typical warning sign: If tomato leaves curl, it can have various causes.
1. Water Stress
Both too little and too much water can cause stress in tomatoes. If the leaves curl upward like a tube and appear limp, it indicates that the plant needs more water. Dry substrate also suggests that the tomato plant should be watered urgently. After a thorough watering, the plant should visibly recover.
If the leaves curl but seem firm and show yellowish discoloration, it may indicate too much water. In cases of waterlogging and subsequent root rot, the soil will smell musty. In this case, refrain from watering and, if necessary, repot the plant in fresh soil.
To prevent water stress, tomatoes should be watered infrequently but deeply. Specifically, this means watering in the garden two to three times a week and in pots daily to every other day, depending on the weather.
Also interesting: How to Tell if Green Tomatoes Are Ripe
2. Heat, Sun, and Wind
Environmental conditions can also cause tomato leaves to curl. Such physiologically induced leaf curling can be recognized by the fact that mainly the upper leaves curl during the day and relax again in the evening. Additionally, the leaves show no other blemishes.
To help tomato plants, providing shade during midday sun can be beneficial. Additionally, avoid over-pruning the plants and leave some leaf mass. When choosing a location, it should be sheltered. A windbreak can help if the plants are already in the garden.
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3. Nutrient Imbalance
Similar to watering, both too much and too little fertilization can be harmful—and lead to curled leaves in tomatoes. Over-fertilizing can result in salt stress. The root tips are damaged by the high salt content. Other symptoms include burnt leaf tips and curled leaves.
Curling leaves can also result from too much nitrogen. In this case, the leaves are also dark green and soft, and the plants bear few flowers. Too little potassium is indicated by light leaf edges, weak tissue, and curled leaf edges.
In the case of over-fertilization, pause fertilizing for the next one to two weeks. Thoroughly flushing potted plants can also help to wash out the nutrients. For deficiencies, add the necessary nutrients using special tomato or berry fertilizers.
4. Diseases and Pests
Aphids, tomato russet mites, and spider mites—all these pests can be responsible for tomato leaves curling. To effectively treat the plant, the culprit must be correctly identified. Tomato russet mites are particularly dangerous as they are often noticed too late to save the plant. They can be combated with predatory mites. Aphids can be tackled with homemade nettle manure. A soap solution helps against spider mites.
If the leaves curl and also have a noticeable mosaic pattern, the tomato mosaic virus may be the cause. Infected plants should be kept away from healthy ones, as the disease spreads quickly. Important: Diseased plants should not be composted. It’s better to dispose of them in the trash. In midsummer, the early blight disease can also occur, recognizable by brown spots and curled leaves that are shed by the plant. Affected leaves should be removed. Additionally, spray the plant with horsetail broth.