Tomato leaves curl up: what to do?

Tomato leaves roll up. This is a common and recurring problem. So long Diseases and pests are not the cause, in most cases this has little effect on the yield.

Care errors as the main causes

If you notice that the tomato leaves are curling up, the first thing to do is to check the care that has been applied.

Strong fluctuations in the water balance

When tomato plants roll up their leaves, they can signal a lack of water. To protect themselves from excessive evaporation in such phases, they roll up their leaves. In older plants, it is mainly the summit leaves that are affected. Young plants tend to have stunted leaves. They can be permanently damaged. As an immediate measure, you should water extensively and in future make sure that the soil is always slightly damp.

Tip: It can lead to drought stress. a. come when the tomato plants are under a canopy and are practically protected from rain. Then it should be watered regularly.

Excessive reduction in leaf mass

Another reason for such leaf changes can be excessive pricking or Be removing too much leaf matter. When pruning, shoots that have formed in the leaf axils are removed. Often the bottom tomato leaves are removed to prevent water from splashing on the tomato leaves, which in turn can cause the dreaded brown rot. However, if too much leaf mass is separated off, nutrients can become jammed. The absorbed nutrients cannot be used due to the lack of leaf mass.

Overfertilization

It is not uncommon for a local excess of nutrients to be the cause of rolled-up tomato leaves. This can result from excessive fertilization but also the sudden release of nutrients due to heat and moisture. This usually has no effect on the yield. Particularly noteworthy are an excess of manganese, nitrogen and zinc.

• Difficult to detect excess zinc
• Excess manganese, especially on acidic soils
• This can be remedied by regulating the pH value
• If there is an excess of nitrogen, a lot of leaf mass is formed
• Tomato plants grow particularly quickly
• Leaves curl down

If the excess nutrients are eliminated, the plants can overgrow the leaf damage. To do this, you should completely refrain from fertilizing and pruning. If mineral fertilizers were used, they can largely be flushed out by penetrating water and shifted to deeper soil layers.

Tip: When using slow-acting natural or depot fertilizers, the risk of over-fertilization is significantly reduced.

Nutritional deficiency

Tomato plants can also react to a deficiency by curling their leaves. Specimens in pots or tubs are affected much more often than those planted in the bed. For this reason, it is advisable to use sufficiently large planters for potted plants in order to offer the plants a sufficient water and nutrient buffer. Rolled leaves can be a sign of a lack of sulfur, calcium, or nitrogen.

Sulfur deficiency

• Sulfur within the plant is less mobile than nitrogen
• Deficiency symptoms therefore appear first in younger leaves
• Then continue on older leaves
• Leaves stiff and curled down
• Less compressed growth than with a lack of nitrogen

Calcium deficiency

• Tomato leaves curl upwards and have brown edges
• Calcium deficiency mainly in pot cultures
• Especially on young leaves
• On acidic soils with a pH below 5
• Tomato plants consume more potassium than phosphorus
• Therefore add with every fertilization
• Chlorine-free potash fertilizers provide help in the event of a pronounced deficiency
• Potassium nitrate well suited, also contains some nitrogen

Nitrogen deficiency

• Tomato leaves turn yellowish and fade
• Curl up as the shortage increases
• The plant now draws nutrients from the lowest leaves
• Pass them on to the youngest leaves and the crown
• The top leaves show growth residue
• Deficiency exacerbated by soils with high or low pH levels
• As well as leaching and low organic matter in the soil
• Easier to fix nitrogen deficiency in older plants

Tip: In order to generally remedy a nutrient deficiency, the prevailing deficiency should be replenished accordingly.

Leaves curling up due to weather conditions

In the spring

Tomato leaves tend to curl up in spring and summer. If it occurs in spring, it may be because the leaves are growing faster than the roots. By bending the leaves, the plant tries to inhibit leaf growth and to support that of the roots. After about two to four weeks, the roots are strong enough and the plant recovers.

In summer

In summer, plants roll up the leaves so that less water evaporates through the leaves. The plant itself is not damaged. Large differences in temperature between day and night can also cause leaf rolls. This type of damage occurs much more frequently in the greenhouse. High temperatures and a lack of irrigation are responsible. The leaves become brittle and can be easily damaged.
This can be remedied by adequate and regular ventilation and watering as required. In the case of plants outdoors, the whole thing is a purely visual flaw. It cannot be remedied, but it is not a cause for concern as long as there are no other symptoms at the same time.

Curling of the leaves due to a pest infestation

Aphids (Aphidoidae)

Aphid infestation on tomato plants occurs mainly in warm and dry weather. It is favored by an unfavorable location and inappropriate water supply. The young leaves are mainly affected. Leaf blisters form, yellow spots appear and the tomato leaves begin to curl. Home remedies such as nettle stock, yarrow broth or neem oil products can be used to combat this. Natural predators such as ladybugs and earwigs can also be helpful.

Spider mite (Tetranychus urticae)

An infestation with spider mites can occur from early summer. If you spray the plant with a fine mist, you can see fine white webs on the leaf edges and leaf axils.

• Lower tomato leaves roll up and dry up
• Leaves lightly speckled
• Infestation by unsuitable locations, too dry soils and unbalanced fertilization favored
• In addition, there is no or inadequate ventilation in the greenhouse
• Remove all parts of the plant that are covered with mite eggs
• Decimate the infestation with a strong jet of water
• Guide the beam from the bottom up
• Plants must then dry quickly, otherwise fungal attack
• Predatory mites (Phytoseiulus persimilis) also promise help

Tip: Spider mites rarely appear alone. They can also transmit harmful viruses that are difficult to fight against.

Tomato rust mite (Aculops lycopersici)

An infestation with the tomato rust mite can usually only be recognized relatively late. The damage is then so serious that you have to dispose of the affected plants. Initially, the stems and petioles turn brown, later the leaves too. The tomato leaves roll up and dry up. If the infestation is severe, the fruits are also affected and the plant dies. An effective control with biological means is not possible.

Diseases as a trigger

Spot disease

The dry spot disease can appear from around the end of June, favored by the pronounced alternation between rainy and dry periods. Brownish or gray-brown spots appear on the leaves, sometimes also on stems and fruits. The fruits are only attacked in the calyx area. If the infestation is advanced, the leaves roll up and fall off. Fungicides are used to control the disease to prevent it from spreading. You have to dispose of affected plants together with their fruits.

Tomato mosaic virus

Infection can be spread through contaminated seeds, gardening tools or planters, as well as dead plant material and aphids. An indication of an infestation is a characteristic mosaic pattern that forms around two weeks after an infection. The tomato leaves curl up, the plants tend to be dwarfed. The only way to combat it is to prevent it. You must dispose of affected plants.

Tip: The tomato mosaic virus can survive in dead, dried-up plant remains for more than 50 years and repeatedly infect or remove plants from the ground. infect.

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