Growing tomatoes has its own subtleties. The plant itself signals that something is wrong with it. Knowing why the leaves turn yellow in tomatoes, curl and become covered with spots, you can immediately take measures to help the garden crop to cope with the disease and subsequently get a high yield. And the causes of yellowing may be different.
The problem of yellowing leaves in tomatoes
Causes of the problem
The main reasons why tomato leaves turn yellow are:
- lack of light and moisture;
- weak roots and other problems with the root system;
- diseases and pests of tomatoes;
- nutritional deficiencies;
- natural biological process.
Under the natural biological process refers to the adaptation of plants to changing conditions. For example, transplanting tomato seedlings causes them to fail in the supply of nutrients. In this case, the lower leaves begin to turn yellow and dry out. This is not scary, the main thing is that the top is preserved viable, and the yellowed leaves of the seedlings will fall off themselves. Otherwise, the plant must be helped: carefully cut off the damaged greens and redirect the food to healthy and developing parts. This measure helps the beds to also be aired and reduces their susceptibility to disease.
The lack of moisture leads to the fact that the leaves begin to curl. Thus, the plants prevent the evaporation of moisture. If water deficiency persists, tops turn yellow. And seedlings wither and fall off the seedbed leaves, and then everything else is damaged. But the excess moisture is not the best way affects the tomatoes. The green mass will actively grow and draw nitrogen from the soil, which will be extremely necessary at the stage of setting and forming fruits. Due to the lack of nitrogen, the appearance of yellow leaves on tomatoes is also possible. Therefore, the role of fertilizing plants with fertilizers is very significant.
Lack of light causes yellowing leaves
How can a lack of sunlight affect the appearance of garden crops? The lower leaves will be the most deficient and will gradually begin to turn yellow.
Pests, diseases and weak root system
Such diseases of tomatoes as late blight can also cause yellowing of the leaves. This is a serious reason to be wary: diseases can destroy the entire crop. In this case, special drugs will help, for example, phytosporin, Bordeaux liquid, xom, etc.
Another reason why the leaves of tomato seedlings and adult bushes turn yellow are pests. With the roots of the tomatoes, the bears and the wireworm will relish with pleasure, the plant can be overpowered by the plant louse. All of this has a negative effect on the general condition of the crops grown, as a result, yellowing of the leaves.
Weak roots can not provide good nutrition of plants. The resulting lack of minerals affects the color of the green mass. Therefore, its yellowing may well be due to problems with the root system.
Weak roots can be in seedlings grown in a small container. The roots are tangled in one. After planting in the soil the seedlings will take a long time to live and ache. In this case, root formation stimulants, such as roots, or foliar fertilizing with nitrates and phosphates can help.
Medvedka - the cause of diseases of tomatoes
By the way, and healthy roots can be damaged by insects or humans by mechanical action on them (inaccurate transplantation, loosening or weeding weeds). In the latter case, do not need to do anything, just wait until healthy roots grow and good nutrition is restored.
On the lack of nutrients that cause yellow leaves, let's talk separately. However, it is difficult for an ordinary gardener to find out exactly what substances the plants lack. Therefore, you need to pay attention to what kind of leaves “sick” - upper or lower. And what are the attendant factors: wither, twist, dry the leaves of a tomato, and so on.
The main reason why the leaves on the tomato seedlings turned yellow is nitrogen deficiency. When this occurs, their grinding, the acquisition of white or yellowish (chlorosis) hue, and the veins become bluish-red. Tomato seedling looks weak, lifeless.
However, nitrogen is necessary not only during growth, but also in the formation of fruits. Therefore, we need fertilizing with nitrogen fertilizers (ammonium nitrate, mullein, bird droppings with added ash, etc.). Stunted tomato seedlings will be encouraged from spraying with the same preparations, but in a weaker concentration.
Insufficient watering - the cause of yellowing leaves
Excess nitrogen can also have a detrimental effect on tomatoes. The stems begin to branch densely, the leaves curl. They appear spots (necrosis), leading to death. What if there is an excess of nitrogen in the soil? The answer is one: wash the soil well.
Why the lower leaves turn yellow
If the lower leaves turn yellow, then, in addition to nitrogen, the plants may lack:
Phosphorus plays an important role in the development of seedlings and adult bushes: thanks to its intake, tomatoes resist colds and diseases, are provided with energy, their root system develops.
What happens with phosphorus deficiency? The leaves of tomato seedlings turn yellow and dry, they are made small, and the edges are bent. Their upper part is painted in a dark green color, and the lower one acquires a purple hue, just like the stems. Then they dry out and fall off. To compensate for the lack of phosphorus can phosphorus-containing fertilizers.
Another reason is the deficiency of potassium, which is responsible for the formation of stems and ovaries. In this case, the lower leaves dry out at the edges. At first they become dark green, then around the edges there are spots that have a brown tint. Over time, the spots form a continuous rim, move to the middle of the leaf, and the leaves curl inward. In this case, potassium humate, potassium sulfate or potassium monophosphate are used to feed the tomatoes.
Fertilizers for tomatoes
Sometimes brownish-grayish spots appear on old leaves, then they die off. The reason is a shortage of zinc. If plants do not feed in time, yellow spots will appear on young leaves. Specialty stores sell special trace elements for tomatoes, including zinc.
With a deficiency of magnesium leaves curl inward and turn yellow between the veins. Tomatoes in this case must be sprayed with a weak solution of magnesium nitrate.
Why the leaves of tomatoes turn yellow (video)
Why the top leaves turn yellow
Yellowing of young upper leaves can be with a deficiency:
If the plants do not have enough calcium, the tips of the leaves are made as if singed. This indicates the defeat of tomatoes apical rot. And it extends to the inflorescences and fruits. And the old leaves are thus made darker. Plants need to feed calcium nitrate.
Leaves wither in tomato and when there is a shortage of sulfur: the upper leaves turn yellow, become brittle, thin. Over time, the yellow color may turn red. The growth of tomatoes at the same time slows down.
Boron is involved in the process of fertilization and pollination of tomatoes. Its deficiency causes lightening of the upper leaflets and their twisting. Tomatoes begin to thrive, as the growth points die off. Ambulance in this case - spraying the bushes with a solution of boric acid. Yellowing tops can also cause a shortage of manganese, iron and chlorine. Here are the main reasons why the leaves turned yellow on the tomatoes. And their twisting without color change usually arises because of the intense heat, temperature difference (in air, in the soil) and with the active kidding of tomatoes. If the tomato leaves wither for these reasons, there is nothing to worry about.
Any gardener knows that it is better not to solve the problem, but to prevent it.
When growing tomatoes, it is necessary to make complex mineral fertilizers, which are designed specifically for this crop.
Why the leaves of seedlings at the tomato turn yellow (video)
It is necessary to follow the recommendations for the cultivation of specific varieties of tomatoes, because there are nuances that you need to know. And with the appearance of yellow leaves on tomato seedlings and adult bushes, urgent measures should be taken to restore the plants.