What can upset beginner gardeners and “experienced” summer residents equally? Tomato seedlings turn yellow! Why and what to do?
Yes. Very often it happens. The leaves of tomato bushes begin to turn yellow both on the windowsill and in the greenhouse. This is without a doubt - something is missing for the plants.
It is necessary to sow tomatoes for seedlings at certain times; if seedlings outgrow, problems begin.
Why does the color of leaves in seedlings change?
The main element of the tissues of a green plant is chlorophyll. Being in the cells of leaves, it under the influence of sunlight turns carbon dioxide and water into organic substances. Yellowing of the plants suggests that chlorophyll synthesis is impaired for one of many reasons. This plant disease is called chlorosis, there are many reasons why it can manifest itself.
Most often occurs as a result of a violation of the nutritional regime of the roots. This occurs during hypothermia or physical damage. If transplantation caused damage to the root system, then the lower leaves turn yellow in plants, it is necessary to wait for the restoration of the roots of the seedling and chlorosis will disappear. With a strong decrease in soil temperature, chlorosis becomes visible on the whole plant.
To find out why chlorosis appeared, it is necessary to examine the leaves of tomato. If yellowing has affected only the lower (oldest) leaf blades, then one of the batteries may be lacking. Most often, yellowing seedlings indicates a lack of nitrogen. In this case, leaf veins take on a bluish-red hue, and even small leaves change color.
Yellowing may occur with a lack of potassium, but in this case the process may go too far as a result of accumulation of ammonia nitrogen in the tissues, as a result, the vegetative mass is dehydrated and leaf curl is observed, the process reaches traces of tissue necrosis.
Another reason that tomato seedlings turn yellow may be a lack of zinc. This deficiency can be identified by the many small yellow dots on the leaf blade. In this case, tissue necrosis (death) occurs throughout the leaf, and the result becomes noticeable very quickly.
Chlorosis, spreading from the base of new leaves, and discoloration of the plates. If the color change of the leaf blade occurs from yellow-green to lemon-yellow and even reaching a yellow-white hue, it indicates a severe lack of iron. Such changes occur exclusively on young leaves, the disease does not appear on the old foliage. In this case, it is necessary to feed the plants with preparations containing iron, seedlings can recover even several hours after the start of treatment.
Several reasons for drying tomato leaves
Tomato seedlings must be properly dived in a timely manner and closely monitor its condition.
Damp and poor lighting. In most cases, seedlings begin to turn yellow with high soil moisture or with a lack of lighting. This more often occurs in the middle and northern regions, since there, in the spring, there is not enough sunlight for plants.
Lack of trace elements. If, with proper care, chlorosis still begins on the leaves, then evaluate how the shade of the leaves changes. Perhaps there are not enough trace elements for seedlings.
Drying the tips of the leaves of seedlings. There may be several reasons, first look at the plants that are nearby, do they have similar symptoms? If there is something similar, then the blame may be too dry air, the situation can be corrected if placed nearby, a container of water.
Yellow and white spots. This happens if the soil is saline.
The appearance of spots on seedlings. This may be due to leaf burns. Plants develop better in the sun, but if you plant seedlings that are not used to the sun's rays, a strong stream of sunlight can burn the leaves. On beds well lit by the sun, seedlings need to be shaded for the first time.
Septoria disease. Dirty white spots that appear on the leaves indicate that the seedlings are infected with this disease, it is transmitted through the soil. The disease spreads in high humidity. The easiest way in this case is to destroy the diseased seedlings.
Blackleg. This is a terrible disease for seedlings. Ill seedlings wither and fall, their roots begin to rot near the surface of the soil, a dark, gradually narrowing stalk band of the affected tissue appears on the stem. To combat the black leg, preventive measures are taken.
Unlocking the root system. Sometimes you can see that on seedlings leaves turn yellow and dry in one day. In this case, it will not be possible to save the seedlings, the reason is the death of the root system of the tomato.
How to prevent the spread of most tomato diseases
Do not forget that the soil for seedlings can not be moisturized, the soil needs to be watered with medium activity, let it dry out a little before the next watering.
Keep the seedlings on the windowsill or in the greenhouse on the sunny side.
At the first sign of illness, seedlings must be saved. It needs to be transplanted with a complete replacement of the soil, the roots must be completely freed from the soil, evaluate their condition, they should be white (if the root system of seedlings is of a different color - there is no point in saving such seedlings). And you need to transplant them into a new steamed soil treated with drugs from diseases. Each seedling of tomato needs to be added with 20-30 ml of potassium permanganate, after which the plants put the southern windowsill or in the southern part of the greenhouse. Use a breathable soil mixture for transplanting.
Perhaps during a transplant of tomato seedlings you accidentally injure their root system. In this case, it is necessary to put it for a while in a light shadow, when the seedlings take root, you can transfer it to a bright place!
At high salinity of the soil, the roots of plants do not absorb moisture, but on the contrary - suck it from a tomato bush and excrete it into the ground. The soil may become saline when irrigated with hard water and when applying a large amount of fertilizer. With this trouble, you need to remove the soil layer 3 cm thick, pour the seedlings with distilled or snow (rain) water, and then feed the seedlings for several weeks.
How to detect nutritional deficiencies
Even experienced gardeners do not always know what and how to feed tomato seedlings.
Often, without analysis, it is necessary to find out what substances are missing tomato seedlings. External signs of nutrient deficiency:
• Nitrogen. The leaf blades at the edges seem to burn out, the leaf itself quickly turns yellow and dies. In order to "cure" a tomato seedling, it is necessary to fertilize with nitrogen fertilizer;
• Potassium. New leaves become "curly", more adult leaves turn yellow and die. Seedlings can be helped if fed with potassium nitrate or potassium sulfate;
• Magnesium. The leaves begin to dry out, turn yellow on the veins and bend, it is necessary to treat with a solution of Epsom salt or magnesium nitrate;
• Zinc. On the surface of the leaves brown spots become noticeable, they dry and die. Foliar top dressing with zinc sulfate solution will help;
• Molybdenum. The surface of the leaves curls and becomes lighter, seedlings must be fed with a solution of ammonium molybdate;
• Iron. Tomato leaves acquire a white or yellow-green hue, foliar top dressing with iron-containing preparations is necessary.
