Tomato plants, Solanum lycopersicum , that curl or curl their leaves are a concern for many home gardeners. The cause for this is often based on maintenance errors or suboptimal locations and can often be easily remedied.
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roll or curl
Although “roll” and “curl” are often used interchangeably when referring to tomato leaves, there is a difference between the two terms. While the leaves curl up or down, sometimes like a snail shell, when they are curled, small waves are created that pull the leaves together. For this reason, deformation of the tomato leaves is often referred to in connection with curling.
leaf rolls
Leaf curl, also known as spoon leaf disease or crown shoot rollers, is considered a typical disease of tomato plants. However, the term “disease” is very broad here, because the cause of rolling is usually not viruses, bacteria or fungi, but care errors. Suboptimal soils can lead to deficiency symptoms. In addition, leaf curling can also be a natural phenomenon that plants use for protection. In order to be able to take the right action, you should examine rolled-up leaves carefully – preferably with a magnifying glass. If the tomato leaves show no other changes, such as tiny spots, there is a high probability that no pathogen is involved. Nevertheless, you should check the leaves regularly to rule out pathogens.
over-fertilization
The most common cause of curling is over-fertilization, more precisely nitrogen over-fertilization, of the tomato plant. If there is (too) much nitrogen in the soil, it grows quickly and develops many shoots and leaves. However, the tomato leaves are soft and limp and curl up.
measures
Temporarily stop fertilizing and water the plants evenly to flush the excess nutrients from the soil. As a preventive measure, you should use organic fertilizers such as horn shavings or flour. Because these decompose slowly and release the nitrogen in smaller doses.
dryness
If tomato plants get too little water, they roll up their leaves.
measures
Gießen is announced as emergency aid. In the tub culture, you can place the pot in a large container with water so that the plant can really soak up. After that, you should change your watering habits to keep the plants from dying of thirst.
Pouring out
Pinching out tomato plants is intended to prevent the plants from branching out too much. However, if too much is used, this can lead to the leaves curling up, especially if there is also an excess of nutrients. Because in this case there are not enough leaves to absorb the nutrients.
measures
Suspend the pinching for a time so that the plant can form enough leaves. You should also water the plant well for a few days so that the excess nutrients are flushed out.
deficiency symptoms
If the plant lacks trace elements, this can lead to leaf curling.
boron deficiency
Causes:
- pH above 7.5 or below 5.5; Dryness in sandy soils or soils over-fertilized with humus
- curling up of young leaves
Measures:
- Immediate fertilization with boric acid, soil improvement with borax
copper deficiency
Causes:
- light, dry, limed, humic soil
- curling of the leaf tips
Measures:
- Foliar fertilization with copper sulphate, soil improvement with copper fertilization
Zinkmangel
Causes:
- Excess phosphate in the soil, soils with high pH
- Curled leaves at the top of the plant
Measures:
- Foliar fertilization with zinc salts, soil improvement with acidic compost, rock flour such as basalt, bentonite or diabase.
Weather-related/natural causes
If leaf curl occurs in spring, this can have a natural cause. Because at this time of year it can happen that the plant develops more leaves than the roots can supply. To compensate for this mismatch, Solanum lycopersicum curves the foliage to retard leaf growth. When the roots are strong enough to optimally nourish the plants, the leaves resume their natural shape. It can take two to four weeks for that to happen.
temperature differences
If there are large temperature differences between day and night in summer, tomato plants bend their leaves. In the field, there is no measure for this phenomenon. For tomatoes in the greenhouse, it is advisable to reduce the temperature differences.
diseases and pests
Tomato leaf curling also occurs as a result of various diseases or pest infestation. However, the change in the leaves in these cases is only a symptom that shows up relatively late. The first signs of disease are often spots or discoloration of the tomato leaves. In the case of pest infestation, you usually see the pests before they roll up. These causes include, for example:
- leaf spot disease
- early blight
- Tomato mosaic virus
- aphids
- spider mites
- tomato rust mite
frequently asked Questions
Yes. If the leaves curl up, this can be a sign of an excess of manganese in the soil. Other symptoms are spots on the edges of the leaves and the drying up of the tomato leaves.
This question cannot be answered unequivocally. If leaf curling or curling occurs during the course of a disease or as a result of pest infestation, you should cut off diseased or infested parts of the plant. If it is a care mistake, you do not need to remove the tomato leaves.
No. Sufficient watering helps against curled leaves. Nevertheless, you should avoid waterlogging, as too much water causes the roots to rot.
