What to do if the leaves on your tomato plants are curling

In this article, we'll look at the main reasons why tomato leaves curl in a greenhouse and what to do to save the harvest. Leaves begin to turn yellow and curl most often due to a disease called late blightHowever, there's no need to rush into a diagnosis, and it's recommended to further investigate the problem.

The main reasons for leaf curling:
1. Improper temperature control. This is a very common cause of this problem, which occurs specifically when growing tomatoes in a greenhouse. Specifically, temperatures above 35 degrees Celsius (95 degrees Fahrenheit) can cause the nutrients in the soil to break down into their constituent parts, making it difficult for the plant to accumulate them. In this situation, it's important to ventilate the greenhouse more frequently (cross-ventilation is especially effective).
2. Your plants may be lacking mineral elements. Specifically, curling leaves indicate a phosphorus deficiency. Another sign is a gray-green tint to the leaf itself, with clearly visible red or purple veins.
3. Excessive pinching of tomato shoots.
4. Frequent, unjustified watering. This leads to root rot, which, understandably, negatively impacts the plant's growth.
5. Frequent prevention from diseases and pests.

If you suspect that the leaves of your tomato plants in your greenhouse are curling (we'll discuss what to do in each individual case)—whether it's a disease or a parasite—then there are two most common causes.

Cancerous bacterial infection. Initially, tomato leaves curl into tubes, and then, as the disease progresses, they begin to simply wither. Note that small ulcers and cracks should be present on the underside of the petioles.

Sometimes, tomato leaves curl because sucking pests—whiteflies, for example—have taken up residence on the plants. The problem may also be caused by damage to the plant's root system. This often occurs when transplanting tomato seedlings into the ground, especially if the seedlings are already overgrown by the time they're transplanted.

What to do?

When the exact reason why the leaves curl is determined tomatoes in a greenhouse, it's easy to understand what to do. If tomatoes have been damaged by high temperatures, it's advisable to shade the plant and also spray it with a solution of two tablespoons of urea per 10 liters of water (light potassium permanganate can be used instead). After a week, the leaves should straighten out.

Also, be sure to ensure your tomato plants receive sufficient minerals. Fertilize the plants with specialized fertilizers.

Important! Fresh or not yet fully decomposed manure is not suitable for fertilizing tomatoes in this situation. It contains too much ammonia and could easily burn your entire plant.

To help greenhouse tomato leaves straighten, you can water them generously. The normal watering for greenhouse tomatoes is once every ten days. If the tomatoes have been affected by a bacterial infection, spray them with an Avixil solution to stop the process. Do not collect seeds from diseased plants, and it's best to get rid of such affected plants.

When pests are the cause of leaf curl, effective measures must be taken to combat them. A variety of effective treatments are available in stores today, depending on the specific pest causing the damage.

Advice! For the latter type of infestation, you can first treat the tomatoes with "Topaz," diluting 2 ml in 10 liters of water. A week later, treat the plants with "Ordan," diluting 25 grams in five liters of water.

If tomato leaves curl and stems become thick, this indicates too much nitrogen in the soil. This leads to poor fruit production. In this situation, you should reduce the nitrogen content in the soil by simply watering the top layer of soil thoroughly once.

To return the plant to a normal life cycle, you can use phosphorus, potassium, or a special ash solution that contains these elements in sufficient quantities.

We've examined in detail why tomato leaves curl in a greenhouse and what to do in each situation. Before taking specific, effective measures, there's no other option but to accurately determine the cause of the problem. We wish you successful restoration of green mass and an excellent harvest!