Growing tomato seedlings is a long process.
Seedlings require constant care and tireless attention. Often the seedlings get sick - then it is necessary to take measures to treat them. Dear readers!
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Reasons why tomato seedlings turn yellow
As is usually the case, there are several reasons why seedlings begin to turn yellow. They are associated with improper care of seedlings, exposure to the environment or pathogenic microflora and pests. Let's look at the main causes of yellowing in more detail.
Tomato seedlings turned yellow due to lack of light
All plants need light. Especially during periods of growth and development. Tomato seedlings very often suffer from lack of sun. Not every summer resident is able to place boxes with seedlings on the south side. This causes the plants to become stretched and their leaves begin to turn yellow.
Solution
If it is not possible to place the seedlings on the south side, then they need to be illuminated. Phytolamps and fluorescent lamps are used. The optimal length of daylight for young plants is 16 hours (18 on a cloudy day).
You can also use various tricks, for example, reflective surfaces.
If you have no problems with lighting the seedlings, then the cause of the problem lies elsewhere.
Too much sun
The opposite situation is excess sunlight. Direct ultraviolet rays overheat the thin leaf blades of tomatoes. There is no natural cooling provided by wind. The result is burns that first cause yellowing of the foliage, and then its drying out and falling off.
IMPORTANT! Specimens with dried leaves cannot be saved, but other seedlings can. Therefore, the seedlings need to be removed from the windowsill.
Solution
The solution to this problem is simpler than it seems. Firstly, the seedlings can be placed deeper into the room. Secondly, it can be shaded. The easiest way is to cover the windows with paper. You can also use Roman or regular curtains, tulle, etc.
That is, your task is not just to provide the seedlings with regular lighting, but to make sure that the light is diffused. This will protect the seedlings from sunburn.
The soil was not selected correctly for tomato seedlings
The selection of soil is very important when growing seedlings. Tomatoes get most of their nutrients from the soil. Incorrect soil complicates this process. The result is yellowing of the leaves.
Tomatoes grow well in slightly acidic soil. Do not use alkaline soil or soil that is too acidic. You should also not use garden soil, as it is too oily for seedlings.
Solution
In case of high acidity, you need to mix an ash solution (1 tablespoon of wood ash per 5 liters of water), leave it for 4 hours and carefully water the soil. You can also mix chalk or plaster.
If the soil turns out to be alkaline, then it is necessary to water it with a solution of potassium permanganate. The color should be pale pink. By the way, such watering will be an excellent prevention against fungal disease.
Tomato seedlings lack nutrition
The yellow color of seedlings may indicate a nitrogen deficiency in fertilizing. Nitrogen is the main material for growing green mass of plants, and its lack primarily affects the appearance of seedlings.
IMPORTANT! Adding too much nitrogen is harmful. The tomatoes will begin to fatten. Nitrogen also negatively affects the yield of tomatoes, since they spend energy on the growth of leaves and stems, and not on the formation of ovaries.
Solution
The solution lies on the surface - add nitrogen fertilizers. It is best to fertilize the leaves, that is, spray the tomatoes. You can use ammonia (it will also drive away harmful insects) or urea.
The seedlings were overfed
Excess nutrients are also harmful. A sure sign that the seedlings are overfed is whitish deposits at the bottom of the containers. They are located where the drainage holes are.
Solution
No more fertilizing. Excess substances will be washed away with water.
Tomato seedlings turn yellow after picking
Any seedling does not tolerate picking well. Tomatoes are no exception. After the procedure, the seedlings almost always wither a little. If the picking was done correctly, the plants will recover within a few days.
But it happens that this does not happen. What's the matter then? The first possible reason is severe damage to the roots. As a result, the root system cannot properly obtain water and nutrients from the soil. The seedling experiences a deficiency of them, which is manifested in the appearance of yellow spots. The second reason is placing the cups with seedlings under direct ultraviolet rays. The plants are already weakened by the picking, and they are still exposed to the scorching sun.
Solution
In this case, the situation can be easily corrected by correct placement of seedlings (shading them) and feeding with a root formation stimulator. The most popular drug is Kornevin. But there are many analogues; you can use Energen or Zircon.
The crops were thickened
In an effort to save money, some summer residents sow tomatoes very thickly and then do not thin them. This leads to competition between seedlings. As a result, some plants do not receive the required amount of nutrients, light and water. As a result, the leaves begin to turn yellow, and the seedlings themselves stretch out. But one should not think that the plants that win such competition will turn out strong and healthy. Quite the opposite. These will be stunted, thin, disease-prone plants.
Solution
Planting density is eliminated in 2 stages. If the seedlings begin to turn yellow even before picking, then thinning can be done by removing the weakest and most stunted specimens. If yellowing begins in seedlings with 2-3 true leaves, then you need to pick them into separate containers. In addition, the cups are placed away from each other so that the seedlings have enough sunlight.
If tomato seedlings turn yellow due to improper watering
After problems with lighting, improper watering is the most common reason that tomato leaves change color. Moreover, both an excess of water and a lack of it lead to such consequences.
REFERENCE. When overwatered, the lower leaves turn yellow first. The foliage loses its elasticity. If there is a deficiency, the leaves wither and dry out.
Solution
It would be better if there was little water. Then it is enough to water the plants, and they will recover quickly enough.
But seedlings tolerate excess moisture worse. The yellowness may not subside for up to one and a half to two weeks! Watering should be stopped until the soil in the container dries out. Be sure to loosen to allow air to reach the roots.
If the tomatoes are completely flooded, you will have to carry out an emergency pick. But even this does not guarantee a solution to the problem. Therefore, you need to water the seedlings moderately and only when the top layer of soil dries out!
Why did tomatoes turn yellow after planting in open ground?
It is very disappointing when seedlings at home grew well and without diseases, and immediately after transplantation the leaves begin to turn yellow.
Most often, there is nothing wrong with this - the seedlings simply take root in a new place. But, if the yellowness does not subside even after a week, then things are bad. This means damage to the roots.
Solution
Again you need to take Kornevin or its equivalent and fertilize it. If after another week the situation has not changed again, it means that the damage to the roots is critical. We must prepare for the fact that the seedlings will die. If by some miracle they manage to survive, the harvest will be much more meager.
Diseases and pests that cause yellowing of leaves
Pathogenic fungi, bacteria and viruses can also cause yellowing of tomato foliage. Most often, the following diseases lead to such consequences: Black leg, Fusarium, Brown spot.
It is quite difficult to distinguish a fungal infection from improper care, but, for example, a black leg can be noticed if you carefully examine the stem of the plant. A black or brown belt appears on it. With fusarium, seedlings do not respond to watering and wither. With brown spotting, grayish spots are visible on the back of the leaf blade.
Solution
In case of fungal infection, there is only one solution - remove the diseased plants and treat the rest of the seedlings with a fungicide solution. You can use potassium permanganate, but Fitosporin is much more effective.
Diseases
Often the cause of drying out of the leaves of tomato seedlings is fungal and viral diseases.
Fusarium
An aggressive fungal disease that affects plants of the Solanaceae family. Spreads from bottom to top:
- the lower leaves of the seedlings become lethargic, quickly turn yellow and fall off;
- the stem dries;
- The leaves at the top dry out and curl.
Plants damaged by fusarium look as if they have not been watered for a long time. A characteristic sign is the drying out of the entire bush, while the ground part retains its volume, only the lower leaf plates fall off.
The damage to the lower part is associated with the penetration of pathogenic fungi into the vascular system of the plant in the root zone.
Prevention and treatment:
- soil treatment before sowing seeds;
- treatment of seed material with Fitosporin;
- carrying out alkalization of the soil, since pathogenic fungi multiply in an acidic environment;
- spraying with soap solution or Bordeaux mixture;
- destruction of affected seedlings;
- watering with chemicals Previkur, Maxim, Quadris;
- spraying with biological preparations: Fitosporin, Alirin, Trichodermin.
Tobacco mosaic
The causative agent is the Tomato mosaic tobamovirus virus, which enters the plant through the soil or when sowing undisinfected seeds.
The disease spreads very quickly: first, yellow spots with a bright border appear on the leaves. As it progresses, the stem part is affected, and the leaves of the seedlings begin to stretch, curl and dry.
Favorable conditions for the development of tobacco mosaic virus:
- excess nitrogen:
- increased air humidity;
- lack of lighting;
- increased air temperature.
Prevention and treatment:
- removal of diseased seedlings;
- treatment with karbofos in the initial stages (75 g per 10 liters of water);
- spraying with a milk-iodine solution (1 liter of milk and 10 drops of iodine per bucket of water);
- fungicide treatment.
Late blight
The most common fungal disease, which affects both young tomato seedlings and already formed plants.
The main symptom is dark spots that abundantly cover the entire leaf blade.
The progression of the disease is very rapid. The next stage is drying of the leaves. The disease spreads from bottom to top.
Prevention:
- compliance with temperature conditions and air humidity;
- thinning of seedlings;
- regular loosening of the soil;
- reducing the concentration of nitrogen in the soil mixture;
- feeding with compounds based on copper, manganese, iodine and potassium;
- spraying with Fitosporin.
Yellow spots appeared on the leaves of tomato seedlings
Yellow spots can be evidence of both sunburn and brown spot. If seedlings receive only diffuse sunlight, treat them with a fungicide and remove the affected plants.
ON A NOTE. Brown spot can be identified by the gray color of the affected area on the back of the leaf.
Answers to frequently asked questions
The leaves of the seedlings have turned yellow, what should I do?
Determine the cause of the problem? Most likely it's due to improper care. This is much more common than diseases and pests.
Will the seedlings survive?
It all depends on the severity of the problem and what caused the yellowing. Lack of nitrogen and drought are easily corrected, but overwatering and fungal infection are serious problems.
Is it possible to plant yellow seedlings in the garden?
If they are not sick with fungal diseases, then it is possible. It is likely that they will take root and produce a harvest.
Plants turned purple
The color transition of the stem and underside of the leaves from green to purple can occur in two cases:
- the temperature regime for young plants is not observed (too low) or sudden temperature changes are allowed.
- tomatoes lack such a nutritional element as phosphorus.
These two causes of color change are very closely related. The stems turn purple because at temperatures below 14 degrees the roots do not absorb phosphorus contained in the soil. This is probably where starvation comes from.
But if the temperature is normal, and the stems have changed color, then you can try spraying. Make a 0.5% solution of phosphorus fertilizers and spray them on the leaves of the seedlings.
With timely intervention and elimination of the causes, this problem disappears without a trace and does not harm the plants.
Most problems that arise when growing tomato seedlings can be solved if detected in a timely manner and do not affect the subsequent harvest. Difficulties arise mainly from inattention and improper care of seedlings.
Common mistakes
- The problem is ignored. If you do not treat the seedlings, you can lose all the seedlings.
- Incorrect diagnosis. Sometimes it happens that the cause of yellowing is determined incorrectly and, for example, watering is increased, although it was necessary to fertilize with nitrogen.
- Panic. The yellowness of seedlings cannot be ignored, but there is no need to panic. It is quite possible that tomatoes get used to new growing conditions after picking or planting in the garden.
Leaves dry out and curl after picking
The reason for this condition is injury to the root system. Tomatoes are characterized by a decrease in immunity after any transplant. The main symptom is loss of turgor in the green mass.
If the plants do not recover within 2-3 days, and the foliage begins to dry out from the bottom up, then it can be assumed that the root system was severely damaged during picking or replanting.
Prevention:
- compliance with the watering regime;
- application of phosphorus fertilizers.
If leaves dry on tomato seedlings, then in 90% of cases we can talk about a violation of the agrotechnical rules for growing this crop. Poor lighting, violation of the watering regime, unbalanced fertilizing are the primary causes of drying out of the above-ground parts of plants, which entail the development of fungal and viral diseases.
