The reasons for the appearance of purple leaves on tomatoes

Among garden crops, tomatoes are probably the most fastidious plants. They are often attacked by all kinds of pests and get sick. Purple leaves on tomatoes are a problem that gardeners are most likely to encounter. The main causes of many problems are improper care, one wrong step on the part of the gardener can result in a loss of crop.

The reasons for the appearance of purple leaves on tomatoes

The root causes of changing the color palette

Why do seedlings have tomato purple leaves? - This question most often confronts many gardeners and not only beginners in this matter. The main task of the gardener is to provide proper care for the sprouts. Healthy seedlings are the key to a good harvest. Some argue that the purple color of the stems and leaves of tomato plants should not cause concern, because this indicates a good adaptability to low temperatures. But, all this is wrong, because changing the color scheme of greens is a serious problem, which can lead to a decrease in yield or even death of plants

To cure a crop, you need to understand why tomato leaves turn purple. The main reason is poor care.

Factors affecting a change in the shade of foliage:

  • poor illumination;
  • low air temperature;
  • high planting density;
  • avitaminosis.

Foliage begins to change color gradually, so it is not always possible to immediately identify the problem, especially when the lower part of the leaves begins to change color. The stem darkens, starting from the basal part. The causes of the disease are interconnected. The color change, first of all, begins when the plant freezes, and this is due to a lack of vitamins in the soil and a decrease in temperature to 14 ℃.

If the leaves of the tomatoes turn purple, you should immediately determine the cause of the pathological condition. Do not forget that some varieties of tomatoes when germinating seedlings acquire a purple-pink color immediately and this is a natural process. In order not to miss the symptoms of the disease, a permanent examination of the foliage and the stem should be done, especially after a pick. Purple leaves and lethargy of the stems can be a sign of damage to the root system.

Temperature mode

In tomatoes, the leaves turn purple below when the rhizome freezes. If the soil is cold, the roots cease to receive nutrients because the plant directs all its forces to heat, the lower part acquires a darker shade. As soon as the problem with heating is solved, the shade of the leaves will return to normal again.

It is best to install fluorescent lamps near the sprouts. A purple hue in tomato seedlings appears due to the low production of chlorophylls, which are responsible for the green color of the foliage. Do not forget that before transplanting into the ground, fertilizer should be applied three times. Organic fertilizers can help warm the roots, but do not overdo it, an excess of organics can burn the rhizome. You can put a film in the glass with seedlings on the soil itself to warm the rhizomes.

When planting in open ground, freezing of tomato sprouts is very often observed. The upper leaves begin to curl when there is a temperature difference day and night, the difference is up to 10 ℃. In such situations, seedlings should be covered overnight with plastic cups or bottle cuts to protect them from the cold. Damaged leaves should be removed.

How does nutrient deficiency manifest

From a lack of sulfur, the leaves begin to curl.

Often the reason for the wilting and color change of the leaves is not a temperature difference, but a lack of nutrients. At the initial stage of growth, nutrients are very actively drawn from the soil. Ideally, the first time the soil should be fertilized with urea at the time of the dive. This helps to increase the viability of the tomato in the future, quick adaptation after a dive, and also contributes to the full development of the root system.

If the plant lacks trace elements, the leaves turn purple from the back. Most often, the plant needs trace elements such as phosphorus, zinc, nitrogen, magnesium and potassium. In addition to changing the color scheme, the lower part of the leaves begins to curl. The stalk becomes brittle, fibrous. Phosphorus is needed by a plant throughout its life. Its lack sharply negatively affects the state of the ground part and the root system. At the initial stages of growth, phosphorus is especially necessary for plants to form a full-fledged root. The lack of this substance leads to poor assimilation of nitrogen, as a result of which the growth of sprouts slows down. Signs of nutritional deficiencies:

  • with a lack of potassium salts, the leaves become brown at the edges, curl;
  • the reason for the color change of the foliage to violet-red is a lack of phosphorus;
  • when spots appear on the leaves, this may indicate a lack or excess of zinc, copper;
  • leaf curl is caused by a lack of sulfur.

With a lack of sulfur, not only the top leaves become thin, but all the rest. The greens themselves begin to change color. Sulfur is the key to protein production. In violation of this process, the production of amino acids slows down. Symptoms of sulfur deficiency are similar to those of nitrogen deficiency in the soil, but changes begin at the apex. Streaks of violet-pink, sometimes bluish tint appear, the plant practically ceases to develop, the stem does not grow in thickness.

How to determine an oversupply

An overabundance of nutrients is even worse than their lack. Too much organic fertilizer in the soil causes the tops to curl, pink-purple spots appear on them.

The thing is that the rhizome can not absorb such a huge amount of substances, and therefore begins to reduce the production of photosynthesis, as a result of which there is a twisting, a change in the color of greenery.


When the leaves turn yellow from the outside, starting from the base, this is a symptom of iron deficiency - chlorosis. Initially, purple streaks appear on green leaves, and then they begin to turn yellow and fall off. Such symptoms are observed if the soil contains too much alkali.

The introduction of large quantities of organic fertilizers, such as chicken droppings, leads to alkalization of the soil. Most often, it manifests itself in the early stages of growth, when round-the-clock highlighting is needed. If you do not begin to gradually switch plants to daylight, sooner or later chlorosis will begin. Eliminating it is quite simple with iron sulfate. A solution should be made with an active substance content of not more than 1%.

Tomatoes require a sufficiently high content of chloride in the soil so that the lower part of the plant can fully develop. Its deficiency is also called chlorosis. Color changes are observed in the intravenous areas of leafy plates. The optimal chlorine content in greenhouse soil should not exceed 0.02%.

Manganese deficiency

Manganese chlorosis is very rare

Manganese is involved in the processes of respiration and photosynthesis. The upper leaves begin to change color from the base. Most often, it manifests itself on young fragile leaves. Symptoms are similar to iron chlorosis, but the veins with a lack of manganese are darker in color.

Manganese chlorosis is quite rare, in places where the soil is not fertilized with trace elements or with an excess of lime. The reason for the lack of manganese can be hard watering. In this case, the veins remain green, and multicolored spots appear on the sheet itself, resembling a viral mosaic.

Lack of boron and calcium

Boron is responsible for pollination, protein-carbohydrate synthesis. With its lack in plants, immunity decreases sharply. The upper leaves fall down, yellow spots appear at the base. Veins on the leaves acquire a dark purple-brown hue from the outside.

Affected areas begin to decay quickly. The upper leaves acquire an unhealthy color, twist down. When touched, the sheets break quickly.

Calcium is needed to stimulate growth. It participates in the development of tissues, their strengthening, and also helps to accelerate metabolic processes and activate enzymes. The deformation of young foliage begins from the outside. The surface dries and acquires a light yellow color. Old leaves, on the contrary, become darker. To eliminate the lack of calcium, it is recommended to make a solution of eggshell for plant nutrition.

How to help sprouts

What to do when the leaves turn purple:

  • first of all, it is necessary to ensure the temperature in the room within 20 ℃ during the day, at night it can be reduced by 2 ℃;
  • the soil should be fertilized with organic matter, this will help to slightly increase the temperature in the soil itself;
  • use a drip irrigation system, make sure that moisture does not get on the tops and stem;
  • install fluorescent lamps in a room where seedlings grow.

If the lower part of the crown and foliage turned purple, it is recommended to carry out an additional pick. Too much crowding of sprouts in a small area is another reason for turning blue. Rhizomes of plants are close to each other, which slows down the process of absorption of nutrients, in addition, this prevents the roots from growing normally.

Another reason why color changes may occur is fungal diseases. They begin to reveal themselves with high humidity. The most dangerous diseases are late blight and alternariosis. In both cases, spots appear on the leaves, they begin to rot and wither. When infected at later stages of growth, tomatoes acquire a purple hue, almost black.

How to avoid growing mistakes

First of all, you need to understand how tomatoes develop. Almost all diseases, including color changes, begin with a malfunctioning root system. Tomatoes differ in the root type of the stem type, which can grow at a distance of 1.5 to 2 m, so do not forget that you need to plant seedlings at a decent distance from each other.

The main cause of problems is improper care. To be able to quickly correct the situation, you need to do regular inspections of plants for color changes. Affected leaves that have curled and turned yellow should be removed, they only slow down the growth of the plant.

If the upper leaves are twisted in the morning and straightened by noon, there is no reason for concern. Pasynkovka and thinning of leaves should be carried out a day before watering and foliar top dressing. This rule is important to observe, otherwise unhealed pores can cause the spread of infection if moisture enters them.


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