Why do tomatoes turn yellow in a greenhouse or a greenhouse and what should I do?


Often even experienced farmers face the problem of yellowing of tomato leaves in greenhouses. Why tomatoes can turn yellow in a greenhouse and what we will tell you about this in this article.

The cause of yellowing of leaves can be:

  1. Untimely transplanting of seedlings;
  2. Damage to the root system during transplantation;
  3. Wrong irrigation organization;
  4. Non-observance of the temperature regime;
  5. Heavy soil;
  6. Lack of nutrients in the soil;
  7. Diseases and pests.

Let's consider each of the reasons separately.


Table of contents

  • Untimely planting of tomato seedlings in a greenhouse
  • Damage to the root system during a tomato transplant
  • Improper watering of tomatoes
  • Non-observance of temperature conditions
  • Heavy acidic soil
  • Lack of microelements in the soil
  • Diseases and pests
    • Late blight
    • Fusarium
  • The reasons why the leaves turn yellow, preventive maintenance and their elimination

Untimely planting of tomato seedlings in a greenhouse

Growing seedlings at home should remember the timing of the transplant. Start planting seedlings in greenhouses or a glasshouse made of polycarbonate

at the age of 55-60 days. In overgrown seedlings, the root system is collected in a lump due to a lack of space in the tanks and begins to die.

At the time of transplantation of seedlings, new roots and young foliage grow in the greenhouse. To the old leaves no longer reaches the right amount of nutrients. Therefore, they turn yellow and die.
Planting seedlings of tomatoes in the greenhouse is performed at the age of 55-60 days

In this case it is necessary to carry outroot irrigation. We prepare the solution:

  • water - 10 liters;
  • fertilizers - 100 gr.

With this solution, we irrigate the root system. The seedlings will continue to develop well, but there will be a delay in the development of the bush for several weeks.


Damage to the root system during a tomato transplant

Mechanical damage to the roots can occur as a result of inaccurate planting of seedlings, or careless loosening of the soil. In this case, the lower part of the seedling and the leaves may turn yellow.

When the new root is grown, the plant will soon return to normal. Help the plant to recover by irrigation with the drug "Kornevin"And spraying the leavescomplex feeding.


Improper watering of tomatoes

Tomatoes are a culture that easily tolerates drought. Despite the fact that the root system of plants is quite powerful and goes deep, most of the roots absorbing moisture are close to the soil surface. Therefore, irregular watering adversely affects the plant.

Also tomatoesdo not like an overabundance of moisture. Watering should be done rarely, but abundantly. In hotbeds, moisture evaporates much more slowly than in open beds, so an overabundance of moisture can lead to fungal diseases.

Watering a tomato should be done solely at the root

Watering must be carried outunder the root. The water that has fallen on the leaves causes them to turn yellow.


Non-observance of temperature conditions

If there are sharp temperature changes in the greenhouse during the day and at night, this negatively affects the seedlings. If the leaves turn yellow and dry out, this isspeaks about overheating of seedlings. When supercooling, the leaves turn yellow, lose elasticity and fade. This indicates a poor performance of the root system.

The highest permissible temperature in the greenhouse is + 30-32 degrees. The lowest is + 16-18 degrees.

To prevent temperature fluctuations in the greenhouse, you can usebarrels of water. In the daytime, water is heated, absorbing heat, at night gives it away.


Heavy acidic soil

TomatoesDo not tolerate heavy soil and high acidity. The soil for tomatoes is better prepared by yourself before planting.

It is necessary to mix in equal parts garden land, peat and sifted river sand and add ash to normalize the level of acidity. Soil is necessaryloosen after each wateringto prevent stagnation of moisture in the soil, leading to acidification of the soil.

When loosening, additional oxygen enters the roots

When loosening, additional oxygen enters the roots, which ensures normal growth of the plants. The absence of these measures leads to yellowing.


Lack of microelements in the soil

For tomatoes, it is very important to have enough minerals in the soil. Their lack leads to yellowing of the leaves.

Signs of micronutrient deficiency:

  • Nitrogen deficiency. If there is a shortage of nitrogen in the soil, the plant will be weak, with a thin stem, shallow foliage. The first leaves turn yellow and the veins become bluish. Eliminate this disadvantage by performing a watering solution Mullein: for 10 liters of water, 1 liter of fermented mullein and 200 grams of ash.
  • Lack of magnesium. The leaves are covered with brownish-brown spots and fall off. Eliminate by applying fertilizers with magnesium nitrate.
  • Potassium deficiency. The sheet is covered with yellow spots and twists. Before the start of the fruit, it is necessary to make top dressing based on potassium chloride, then you can use potassium phosphate.
  • Lack of sulfur. The leaves are covered with brownish-brown spots and fall off. In the process of fructification, two times to make top dressing with a high content of sulfur.
  • Lack of boron. The leaf on the top of the bush turns yellow. Add boric acid-based top dressing.
  • Manganese starvation. The leaves have a light yellow color. Young leaves are the first to be affected, and then old ones.
. . Yellowing with nitrogen deficiency.. Tomato leaves with a lack of potassium.

In the latter case, it is necessary to introduce into the soilfermented mullein solution, diluted in the ratio:

  • mullein-1 liter
  • water - 20 liters

It is also recommended to spray tomato bushessolution of potassium permanganatein relation to:

  • Warm water - 10 liters
  • manganese - 1 tablespoon

Diseases and pests

Yellowing foliage can occur as a result of the appearance in the soil of such pests as:

  • the bear;
  • wireworm;
  • nematodes;
  • tobacco aphid.
. . Medtotox.. Bazudin.

A wireworm, a nematode and a honey bear feed on the root system of plants, damaging it. With each of these pests are struggling by different means.

Against a bear, it is recommended to apply the drug "Medtox". To combat wireworm use "Bazudin". If a nematode is found in the greenhouse, it is recommended thatreplace the soil. With this type of pest it is extremely difficult to fight.

If the root system of plants is not damaged and there are no pests in the greenhouse, and the leaves continue to turn yellow, this indicates the presence of fungal diseases.

These diseases include:

  • late blight;
  • fusariosis.

Late blight

With this disease on the leaves appear brown spots, which affect in the aftermath and fruit. The cause of this disease isincorrect watering.

It must be remembered that watering should be carried out under the root, not falling on the leaves. In case of late blight, bushes need to be treatedBordeaux liquid.

Late blight infection

At home, you can make it yourself. When preparing this solution, you must precisely observe the proportions. To obtain a 1% solution, the components are diluted in the following ratio:

  • water - 10 liters;
  • copper vitriol -100 grams;
  • Quicklime lime -150 grams.

For spraying tomatoes in 1 square. meter will need 2 liters of solution.


With this disease, tomato leavesThey lose their elasticity and change color. The cause of this disease are:

  • an infected tool;
  • infected seeds.
Penetrating into the soil, the fungus can be present in it for a long time, since the high humidity and high temperature in the greenhouse are ideal conditions for its life.
Leaves tomato with fusariose

This disease can appear in both an adult plant and a seedling. You can get rid of this problem with the help of "Previcur Energy"And"Trichodermine".

The reasons why the leaves turn yellow, preventive maintenance and their elimination

  • Shortage of microelements. With this problem, regular supplementation is necessary.
  • Pest Control. The regular destruction of weeds, the implementation of soil disinfestation, the strengthening of plant immunity, the normalization of the microclimate in the greenhouse will help to avoid this problem.
  • Diseases. To prevent diseases, it is necessary to timely disinfect the greenhouse, seeds and soil. Do not allow thickening of plants, as well as regularly ventilate the greenhouse.
  • Root damage. This problem can be avoided by growing seedlings in separate containers. Transplant with a clod of earth from the previous place of growth. Gently produce loosening.
  • Temperature differences. Regularly perform ventilation. Install in the greenhouse barrels of water.

Taking preventive measures to eliminate the causes of yellowing of leaves, you can collect a good harvest of tomatoes in the greenhouse with excellent taste qualities.

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