Tomatoes are a plant familiar to everyone, originally from South America, loving rich and moisture-resistant soil.
Healthy growth of tomatoes requires sunny weather and temperatures from + 21 ° C to + 24 ° C. Planting seedlings in a greenhouse or open ground is possible only when at night the temperature does not drop below + 7 ° C.
Tomatoes turn yellow leaves: why?
The main reasons why this symptom manifests itself:
• lack of nutrients;
• damage to the roots during diving, planting or loosening;
• a disease caused by a fungus or virus;
• insufficient temperature or lighting;
• excess moisture or lack thereof;
• pests;
• burns.
Most often, yellowness appears due to the scarcity of soil, especially for open ground or greenhouses with large areas, where it is much more difficult to monitor the quality of the earth. Lack of nitrogen is manifested precisely by this symptom, and the old leaves fall off after a while, their edges look slightly dried. If you ignore this problem further, the plant stem will begin to weaken and become thinner by stretching the bush, while the leaves will be rare, small and pale. Due to the lack of potassium, the edges of the old leaves turn yellow, and the young curl into a tube. At first, small yellow-brown spots appear along the very edge of the leaf, but over time they merge into one line. As a result, the leaves slowly dry.
Due to the lack of magnesium, yellowness appears between the veins, while the leaf curls, protruding upward. The same symptom indicates a lack of molybdenum, but such a problem is rare. Sulfur starvation first manifests itself in the form of a weakly green color of young leaves, then they begin to turn yellow, while the veins become a reddish hue. In the event of a prolonged shortage of this microelement, the stem of the tomato bush will weaken and become fragile. Due to a lack of iron, glandular chlorosis develops, which manifests itself in the form of pale yellowish leaves with green veins. This problem is dangerous because the top of the plant begins to turn pale, and the bush completely stops its development.
Lack of potassium causes not only the manifestation of light yellow spots on young leaves, but also spoilage of fruits by apical rot, and it can be transmitted from one fruit to another. The top of the tomato acquires a brown color and is pressed inside. Fruits become completely unsuitable for fresh consumption or are completely thrown out (it is best to burn).
Tomato seedlings turn yellow - what to do?
If there is a shortage of any trace element, it is necessary to feed them with fertilizer containing it. So, for example, nitrogen starvation can be eliminated by spraying with urea. To do this, add 1 tablespoon to a ten liter bucket of water. Mullein can also be used. First you need to soak it - 1 bucket of manure 4 buckets of water. So leave for 3 days. Before fertilizing, it must be diluted in proportion - 1 bucket of soaked mullein to 3 buckets of water. For 1 bush of tomato, 1 liter is enough. The soil must be moist before top dressing. Watered under the root of the plant, not on the foliage.
What to do if tomato seedlings turn yellow due to a lack of potassium? It is replenished with the help of potassium nitrate. For spraying, you will need to dilute 1 teaspoon per 1 liter of water, and for watering 1 tablespoon per ten liter bucket. The potassium level in the soil is well compensated with ordinary wood ash.
What to do if tomato leaves turn yellow and vertebral rot appears?
In this case, it is necessary to use calcium nitrate or other complex fertilizer with its content. Of the folk methods, the most popular is the introduction of crushed eggshells into the ground.
To eliminate iron deficiency, a 0.1% solution of iron sulfate or iron chelate is used. The second is bred in proportion to 1 liter of water 1 g of fertilizer. If there is no such top dressing, then you can use rusty nails. They are laid in the ground closer to the roots. Copper is replaced in the same way, only copper wire is used instead of nails.
Tomatoes turn yellow leaves in the open ground - weather reasons
Tomatoes are plants that prefer mostly sunny and warm weather. So, if the weather is cold for a long time, the metabolism in the plant may be disturbed. It begins to not only turn pale and drop leaves, but also inflorescences. And if the weather is damp, then diseases develop, moreover, the roots may begin to rot. Extremely hot and dry weather, as well as occasional watering, can lead to burns of tomato bush leaves. Most often, this problem occurs in greenhouses installed in an open area. Due to the increased humidity, a brown olive spot may appear or, in another way, is called cladosporiosis. Especially strong and fast this fungal disease occurs in dimly lit greenhouses.
Tomatoes turn yellow leaves in a greenhouse or on the street: what to do - pests and diseases
One of the most dangerous diseases of tomatoes is fusarium. It manifests itself especially quickly in greenhouses or hotbeds with high humidity, temperature and poorly ventilated. What to do if tomato seedlings turn yellow due to this disease? If the plant is severely affected by it (it began to fade), then it is best to remove it with a lump of earth. If the first signs appear, then watering the bush with Fitosporin can still help. The source of this disease is often the seeds themselves, so you should always process them before sowing.
Due to densely planted tomatoes and high humidity, late blight can appear. This disease can destroy a large part of the crop. What to do if tomato seedlings turn yellow due to late blight? If only leaves are infected, then they should be removed without leaving a single infected leaf. Immediately after this, you need to process, for example, phytosporin or the drug "Hom". Blown tomatoes can be infected from potatoes, so when planting, be sure to separate them.
The main pests of tomato seedlings are aphids, whiteflies, spider mites, bear cubs and wireworms. The first suck out the juices from the leaves of the plants, because of this they begin to turn yellow and dry. You can treat the infected bush with Akarin, and you should also find an anthill, from where the ants carry it. They can be removed using the pesticide "Ant". Acarin will also help against whiteflies and spider mites. Wireworms damage the plant roots by gnawing and making holes in them, sometimes they can even penetrate the stem. As a result, the tomato bush withers and dries. To avoid this, during the planting of seedlings around the root, pour any drug from this pest, for example, Bazudin. The main thing is to comply with the recommended dose. The bear also spoils the roots of the tomato. Of the chemicals, Medvetox is often used against it.
Tomato leaves turn yellow: what to do if the reasons are not established, prevention
If the reasons why the leaves turn yellow in tomatoes are not clear, then you can carry out preventive treatment and plant nutrition. Including the removal of the affected leaves, especially if these are leaves of the lower tier. If the plant began to turn yellow in late August or early September, then it could already simply ripen. To avoid the appearance of diseases that cause yellowing of the leaves, it is better to carry out constant treatment with biological drugs, for example, every 2 weeks or only 4 times per season. So the plants will be prepared for adverse weather conditions.
You should purchase those varieties that are resistant to most diseases, and the seeds must be treated with a 1% manganese solution before planting.
Do not water the tomatoes too often, the soil should be moist, loose, but not too damp and without crust.
Also, you can not plant seedlings close to each other (less than 40 cm), because of this, ventilation is disturbed and a disease may appear, moreover, the plants begin to stretch and become thin and weak.
