If at the beginning or in the middle of the gardening season the leaves of tomatoes start to turn yellow, this is at the very least not normal.
Sometimes the problem is solved by regular watering, but there are cases when pouring water makes no sense at all. Let's figure out how to determine the cause and deal with the problem.
1. On grown seedlings
Yellowing cotyledons on seedlings should not cause alarm. These are leaves that appear on the shoots of future seedlings and are not yet leaves. They may even fall off soon, and this is also part of the life cycle of seedlings. Only yellowing of fully formed leaves should cause alarm.
2. Incorrect watering
Excess moisture has never been beneficial to any plant. Roots, leaves, and stems can suffer. Lack of oxygen causes yellowing at the edges. Tomatoes should be watered only after the soil has dried out to a depth of 2.5-5 cm.
3. Dense soil
The problem may again be related to the saturation of the soil with oxygen. It is solved by simply loosening the soil.
4. Adaptation after transplantation
Transplantation is stressful for any plant. Especially if the seedlings were planted in cool soil. Yellowness appears mainly on the lower leaves. This does not harm the bushes and you can even remove the yellowed leaves.
5. Lack of nutrition
First of all, such consequences are caused by a lack of nitrogen. With a lack of magnesium, iron, zinc, the leaves turn yellow, while the veins remain green.
6. Diseases
If the changes are caused by a fungus, the problem starts with the lower leaves. It could be fusarium, verticillium or bacterial wilt. Fungicides are used to solve the problem.
Lastly, there is absolutely no point in worrying if the leaves start to turn yellow at the end of the gardening season.
