Why are my tomato plants turning yellow?

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Tomato plants turning yellow can be a frustrating problem to have. There are many reasons why this might happen, but the good news is that it’s often an easy fix! In this blog post, we will discuss what causes tomato plants to turn yellow and how you can solve the problem.

Peculiarities of growing tomatoes

Tomatoes for growing in the open ground are suitable only for experienced gardeners. If you are just starting to grow such a vegetable, you need to start with a greenhouse, where growing is easier. The fact is that tomatoes are very capricious. They do not tolerate wind, excessive moisture. Tomatoes are very fond of heat and sun, so in advance you need to think about all the measures to protect the delicate plant.

Peculiarities of growing tomatoes
Photo from @garden_alf

It is also important to choose a suitable variety of tomato. It is selected based on the region in which you live. After all, if it is too cold, it is important to choose a variety that can grow at such a temperature. And vice versa, for a hot region there is a particular variety.

Tomato lower leaves turn yellow

If you notice that your young tomato has yellowing lower leaves, this is not a reason to panic. After all, the young shoots form yellow leaves on purpose, because this is the process of maturation of the plant. And these lower leaves are not actually true leaves, but are called cotyledons. They are the very first pseudo leaves that form from the seeds.

Tomato leaves turn yellow if watered too much or not enough

Excess moisture can cause root rot and cause all or part of the roots to die. If you don’t take action, it will cause the entire plant to wilt and die! After all, when you pour a lot of water, the roots don’t get valuable oxygen and suffocate, and after that their rotting begins. Accordingly, the leaves do not get enough nutrition and oxygen, they begin to turn yellow and fall off.

Also pay attention to underwater watering, because most often it leads to damage of the tomato root system.

Tomato leaves turn yellow if watered too much or not enough
Photo from @anyonecangarden

Water the plant only when the top layer of soil is 1-2 inches dry. Water the plant only under the root, not on the leaves. Try to water in the morning so the water doesn’t evaporate. It is important to water tomatoes well so that the water penetrates deep into the soil and the roots grow well.

Other causes of yellowing tomato leaves

Fungus

If your tomato leaves turn yellow and have oily spots on them, you probably have a fungus on your plant. It can be treated with fungicide, but it’s best to take preventative measures to avoid this problem in the first place. Make sure you water your plants regularly and don’t over water. It is also important to keep a distance between the plants so that air can circulate well between them.

Fungus
Photo from @evengreener_store

The fungal disease phytophthora is especially dangerous for tomatoes. It starts at the top of the leaves and gradually spreads throughout the plant. It can be recognized by oily spots on the leaves. It can be treated with fungicide and chlorothalonil.

Viruses

If your tomato leaves turn yellow and have brown spots on them, your plant is probably infected with a virus. There is no cure for viruses, so the best thing you can do is remove the infected plant and destroy it. Be sure to disinfect your tools after removing the plant and don’t use the same tools on other plants.

Viruses
Photo from @gardening_with_rh

Viruses can get to the plant from human hands and dirty tools. They can also be carried by pests such as whiteflies, aphids, and thrips. Such a viral disease has names: tobacco mosaic, cucumber mosaic, yellow leaf curl and single streak virus. All of these viruses stunt the growth of the plant, deprive it of fruit, and can also cause leaf disfigurement

Pests

If your tomato leaves are turning yellow and have holes in them, it’s probably due to pests. There are many different kinds of pests that can affect tomatoes, but the most common are aphids, whiteflies, spider mites, thrips and flea beetles. These pests can be controlled with special solutions bought at a gardening store, or you can treat them with insecticide or garden soap.

If there are large pests on tomatoes, such as hornworms, they are removed manually. Or you can turn to special mixtures and solutions.

Nutritional deficiencies

If your tomato leaves are turning yellow, there may be something wrong with the soil. One common deficiency is a lack of nitrogen. Symptoms will begin to show first on the older leaves of the plant. They will turn pale green or yellow and eventually die. To solve this problem, add some organic matter, such as compost or manure, to the soil. But before treating, be sure to test the soil to determine its exact composition.

Nutritional deficiencies
Photo from @buttenshawbackya

The second reason is a lack of fertilizer. Tomatoes are considered to be voracious plants, so it is important to fertilize them every month throughout the growing season. But follow the instructions strictly, because overfeeding will lead to other problems with tomatoes.

Soil compaction

If your tomato plants are dying, they may be growing in compacted soil. This most likely happens when the plant is still young. The roots can’t grow normally in compacted soil, resulting in slower plant growth. If you suspect compacted soil, dig a few inches around the base of your root by loosening the soil with your hands. But be careful not to damage your tomato roots.

Soil compaction
Photo from @kalgardener

It’s best to plant tomatoes in beds or in pots. And if in open soil, it should be well seasoned with organic fertilizer.

Shocked state of the tomato when transplanting

Shocked state of the tomato when transplanting
Photo from @boonshydrofreshp

Tomato plants do not like to be moved from warm to cold soil. Observe the tomatoes; if they continue to turn yellow, there is another reason. And if the yellowing will go away, then the transplanting was the cause after all.

Nicolas Wayne

Gardening and lawn care enthusiast

Nicolaslawn
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