Why do the leaves of tomato seedlings turn yellow

Tomato is always a welcome vegetable on our table. And although it appeared in the diet of Europeans not so long ago, it is difficult to imagine a summer without a salad of fresh tomatoes or a winter table without canned tomatoes. What about borscht and cabbage soup without tomato juice or tomato paste? What about the various sauces we are so used to? No, the sudden disappearance from our diet of this wonderful vegetable in every way would be a disaster. In addition, tomatoes can be grown in almost any climatic zone, if not in open ground, then in a greenhouse or greenhouse. We often grow tomato seedlings on our own. And while caring for her is not too difficult or burdensome, problems do not occur as rarely as we would like. In this article, we will find out why tomato seedlings turn yellow.

What Do Tomatoes Need to Grow Successfully?

To get a good harvest, you need healthy seedlings, and for this it is desirable to clearly understand what the plant loves and what should not be allowed when growing it. Let’s first understand what tomatoes love:

• Soil with a neutral reaction or slightly acidic;
• Phosphorus fertilizers;
• Bright sun;
• Fresh air supply;
• Economical, uniform soil moisture;
• Warm, dry air.

Don’t like tomatoes

• Excess fertilizer, especially nitrogen;
• Top dressing with fresh manure;
• air stagnation;
• Thickened landings;
• Waterlogging of the soil;
• Watering with cold water;
• Irregular watering;
• high humidity;
• Prolonged cooling;
• Heat above 36 degrees;
• Acid, heavy soils.

Causes of yellowing of the leaves of tomato seedlings

Tomato seedlings turn yellow for various reasons, often unrelated to each other. Most often it is:

• The quality of soil for growing seedlings;
• Improper watering;
• Lack or excess of nutrients;
• Insufficient lighting;
• Close fit;
• Other reasons.

Yellowing of the leaves does not always lead to the death of tomato seedlings or even to some serious consequences, but only if measures were taken immediately. In any case, we need to know exactly what mistakes we made so as not to repeat them in the future. Let’s take a closer look at each of the possible reasons why tomato seedling leaves turn yellow.

Soil for growing tomato seedlings

To grow high-quality seedlings, you can’t just take garden soil or soil from a greenhouse. Seeds need to germinate, and it is not so easy to do this through dense soil. In addition, tomato sprouts are tender and their roots are weak. It is also impossible to take purchased soil left after planting indoor flowers – it is intended for adult plants, it may be too heavy or acidic for seedlings. In addition, fertilizers have already been added to it in a concentration suitable for growing an adult plant.

Tomato seedlings turn yellow if the soil:

• sour;
• contains a lot of fertilizers;
• too dense;
• covered with a crust due to its mechanical properties or watering with hard water, which worsens the supply of oxygen to the roots and can cause not only yellowing of the leaves, but oppression and death of the whole plant;
• alkaline – this can cause chlorosis.

Mistakes in watering, as the cause of yellowing of the leaves of tomato seedlings

As we wrote above, watering tomatoes like moderate and uniform. If they are regularly flooded, the soil will turn sour and air will not flow to the roots, the sprouts will slowly die, and this will begin with yellowing of the lower and cotyledon leaves.

It is also impossible to water poorly – and this causes the leaves of tomato seedlings to turn yellow. Watering should not be excessive, but sufficient. Firstly, with a lack of moisture, the leaves can simply dry out, and, secondly, the absorption of nutrients in dry soil is significantly impaired. Nitrogen and phosphorus from the leaves moves into the stem, which causes them to turn yellow.

If you water the tomatoes with hard water, salts can form on the soil – they can be determined if the surface of the soil is covered with a whitish crust or white or yellowish spots appear on it. The roots draw nutrients from the plant and release them to the soil.

Mistakes in feeding seedlings that can lead to yellowing of the leaves

The leaves may turn yellow due to a lack or excess of nitrogen. The nutrition of tomatoes must be balanced, the plant needs nitrogen at all stages of development – it is part of proteins and chlorophyll. Interestingly, nitrogen is very mobile, the plant independently transfers it to where it is needed most: for example, from old leaves to young ones. Thus, with nitrogen starvation, the lower leaves turn yellow first.

The tips of tomato leaves may turn yellow or dry out due to a lack of potassium, which, in addition to a lack of this element in the soil, can be caused by acidic soil. In this case, potassium is not used for food, but for soil deoxidation.

Consequences of insufficient lighting for tomato seedlings

Tomato is a long daylight plant. He needs good lighting for at least 12 hours a day for normal life. We all know this, we understand everything, but for some reason we often put it in an insufficiently lit place, and then ask why the leaves of the tomato seedlings turn yellow.

Especially often this problem is faced by residents of the northern regions, where daylight hours in spring are very short. Exit – highlight the tomatoes with a fluorescent lamp. Even better – buy a phytolamp, now its price is not very high, but it will last for many years.

It should be noted that it is impossible to highlight tomatoes around the clock – we risk that the leaves will turn yellow from chlorosis – a lack of iron, which simply ceases to be absorbed.

Consequences of close planting of tomato seedlings

Don’t sow the seeds too thick! The authors of all articles on growing tomato seedlings do not get tired of writing about this, but we make such a mistake again and again. Seedlings are stretched due to lack of light, it is cramped, which in itself can cause yellowing of the leaves. In addition, the feeding area is significantly reduced and the root does not develop normally.

Other causes of yellowing tomato seedlings

An article talking about the causes of yellowing of tomato leaves will not be complete if we do not dwell on rare moments. So, the cause of yellowing of the leaves may be:

• Poor quality fertilizer or fertilizer that we simply did not dissolve well in water. As a result, grains containing nitrogen fell on the leaves and burned them;
• Watering at noon on a sunny day – the leaves can get a sunburn. It can be mistaken for yellowing of the leaves;
• Our beloved cat or cat has confused the seedling box with the toilet. By the way, this happens quite often if the animal gets free access to the room where we grow seedlings;

  

• Fusarium wilt of leaves. It rarely occurs in seedlings, most often adult tomatoes are affected by it.

What to do if the leaves of tomato seedlings turn yellow

Tomato seedlings turn yellow, what to do? We have already figured out the reasons, now let’s save the seedlings.

If we poured the tomatoes not very much, the leaves turned yellow, but the soil did not turn sour, powdering the soil with ash and reducing watering can help.

An urgent transplant into a new soil will be required if:

• The overflow is strong, the soil is sour;
• We initially sowed seeds or seeded seedlings in acidic or overly alkaline soil;
• The seedlings were overfed or watered with hard water, which caused soil salinization;
• Plants are very closely spaced or in insufficiently large pots.

To do this:

• Prepare a container with soil suitable for growing seedlings, moisten it slightly;
• Remove young tomatoes from the old soil, clean the roots and destroy all plants with a black leg or rotten root;
• Plant seedlings in new soil;
• With a teaspoon or a tablespoon, depending on the size of the transplanted tomato, pour each sprout individually with a solution of foundationazole or a slightly pink solution of potassium permanganate;
• Shade the planting for a few days and limit watering;
• When the seedlings recover from transplanting, provide them with maximum light for 12-15 hours a day.

If the yellowing of tomato leaves is caused by a lack of fertilizer, feed the plants. It is even better to give the seedlings foliar top dressing with chelates at the same time – they are usually sold packaged in bags designed to be dissolved in two liters of water.

Whatever the reason for the yellowing of tomato leaves, treat them with a solution of epin over the leaf – it will smooth out the effects of any negative factors.

We offer you to watch a video that can be useful both when growing seedlings and when caring for tomatoes in the ground:

As you can see, in order for tomatoes to develop normally, you just need to follow all the rules for sowing seeds and caring for seedlings.