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Tomato leaves curl up. This is a common and recurring problem. As long as diseases and pests are not the cause, in most cases this has little effect on the yield.

In a nutshell

  • curled leaves on tomato plants are called spoonfuls
  • so-called spoon-leaves are always a sign of stress
  • Symptom can occur due to care, illness or weather
  • highly dependent on the variety, some severely affected, others not at all
  • Fruits are not damaged in most cases

Mistakes in care as the main causes

If you notice that the tomato leaves are curling, the first thing to do is to check the care you have been given.

Strong fluctuations in the water balance

If 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, the top leaves are mainly affected. Young plants are more likely to have stunted leaves. You can be permanently damaged. As an immediate measure, you should water extensively and make sure that the soil is always slightly moist in the future.

A lack of water can cause the tomato leaves to curl up.

Tip: Drought stress can include: come when the tomato plants are under a canopy and practically sheltered from rain. Then it should be watered regularly.

Excessive reduction of leaf mass

Another reason for such leaf changes can be excessive pinching or the removal of too much leaf mass. With pinching, shoots that have formed in the leaf axils are removed. Often the bottom tomato leaves are also removed to prevent water from splashing from the ground onto the tomato leaves, which in turn can cause the dreaded brown rot. But if you cut off too much leaf mass, it can lead to a nutrient blockage. The absorbed nutrients cannot be utilized due to the lack of leaf mass.

over-fertilization

It is not uncommon for a local excess of nutrients to be the cause of curled tomato leaves. This can be caused by over-fertilization, but also by the sudden release of nutrients due to heat and humidity. This usually has no effect on the yield. An excess of manganese, nitrogen and zinc is particularly worth mentioning.

  • Excess zinc difficult to detect
  • Excess manganese, especially on acidic soils
  • This can be remedied by regulating the pH value
  • With excess nitrogen, formation of a lot of leaf mass
  • Tomato plants grow particularly quickly
  • Leaves curl down

If the excess of nutrients is eliminated, the plants can overgrow the leaf damage. To do this, you should first completely refrain from fertilizing and exhausting. If mineral fertilizers were used, these can be largely washed out by penetrating watering and relocated to deeper soil layers.

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

When fertilizing, you have to pay attention to the right dose.

nutrient deficiency

Tomato plants can also respond to a deficiency by curling their leaves. Specimens in pots or tubs are affected much more frequently than those planted in beds. For this reason, it is advisable to ensure that potted plants are in sufficiently large planters to provide the plants with a sufficient water and nutrient buffer. Curled leaves can be a sign of sulfur, calcium, or nitrogen deficiency.

sulfur deficiency

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

calcium deficiency

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

nitrogen deficiency

  • Tomato leaves turn yellowish and fade
  • Curl up as shortage increases
  • Plant now draws nutrients from the lowest leaves
  • Passes them on to youngest leaves and into the crown
  • Top leaves show growth retardation
  • Deficiency aggravated by high or low pH soils
  • As well as by leaching and low organic matter in the soil
  • Easier to fix nitrogen deficiency on older plants

Tip: In order to generally remedy a nutrient deficiency, the prevailing deficiency should be supplemented with fertilizer.

Weather-related curling of the leaves

In the spring

Tomato leaves often curl up in spring and summer. If it occurs in spring, it may be because the leaves are growing faster than the roots. By curling the leaves, the plant tries to inhibit leaf growth and 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 their leaves to reduce the evaporation of water through the leaves. The plant itself is not damaged. High temperature differences between day and night can also cause leaf curl. This type of damage occurs much more frequently in greenhouses. Responsible are high temperatures and lack of irrigation. The leaves become brittle and can easily be damaged.
This can be remedied by sufficient and regular ventilation and watering as required. With plants outdoors, the whole thing is a purely visual defect. Although this cannot be rectified, it is also not a cause for concern as long as other symptoms do not appear at the same time.

Curling of leaves due to pest infestation

Aphids (Aphidoidae)

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

Spider mite (Tetranychus urticae)

Spider mite infestation 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.

Spider mites on tomato leaves
  • Lower tomato leaves curl up and dry up
  • Leaves lightly mottled
  • Infestation favored by unsuitable locations, soil that is too dry and unbalanced fertilization
  • In addition, there is no or insufficient ventilation in the greenhouse
  • Remove all plant parts covered with mite eggs
  • Decimate infestation with a strong jet of water
  • Guide the beam from bottom to top
  • 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 combat.

Tomato rust mite (Aculops lycopersici)

An infestation with the tomato rust mite can usually only be recognized relatively late. The damage is then already so serious that you have to dispose of affected plants. Initially, the stems and leaf stalks turn brown, and later the foliage too. The tomato leaves curl up and dry up. In the case of a severe infestation, the fruits are also affected and the plant dies. Effective control with biological agents is not possible.

diseases as triggers

early blight

Beginning around the end of June, early blight can appear, favored by pronounced alternation between rainy and dry periods. Brownish or grey-brown spots appear on the leaves, sometimes also on the stems and fruits. The fruits are only affected in the calyx area. As the infestation progresses, the leaves curl up and fall off. Control is carried out with fungicides to prevent spread. Affected plants must be disposed of together with the fruits.

tomato mosaic virus

Infection can be transmitted via contaminated seeds, gardening tools or planters, dead plant material and aphids. Indication of an infestation is a characteristic mosaic pattern that forms about two weeks after infection. The tomato leaves curl up and the plants tend to dwarf. The only way to combat it is prevention. Affected plants must be discarded.

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

frequently asked Questions

Can tomatoes still be eaten with the leaves curled up?

If it is determined that the leaves have not curled due to disease or pest infestation, the tomatoes are safe to eat.

How can you prevent a nutrient deficiency or excess?

As a basic supply, three to five liters of compost per square meter are sufficient. When planting, you also work an organic fertilizer, such as horn shavings, into the soil. With fruit formation, you can fertilize about every four weeks with a liquid organic fertilizer or appropriately diluted nettle manure.

Do tomatoes have to be pinched out?

Excessive use is not a must, but recommended for single-shoot varieties, especially stick tomatoes. After pinching, the fruits are much larger and more aromatic. The plants need less space and you can prevent fungal diseases. Such interventions are not necessary for bush, vine and wild tomatoes, as they also produce good quality fruit on the side shoots.

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Garden plants