Why Have My Tomato Plants Gone Yellow?

As a tomato gardener, one of the most disheartening things to see is yellowing tomato plants. This can cause concern for those new to gardening, but there are a variety of reasons why tomato plants may turn yellow. In this article, we’ll explore some of the potential causes for this issue.

Lack of Nutrients

If your tomato plants are turning yellow, it could be due to a lack of essential nutrients such as nitrogen, magnesium or iron. Nitrogen is vital for the development of the chlorophyll that gives plants their green color. If your soil is lacking in this nutrient, it may cause a yellowing of the leaves.

Magnesium is also an essential nutrient, and a deficiency can cause yellowing between the leaf veins, leaving the veins themselves green. This is known as interveinal chlorosis. Similarly, a shortage of iron can also cause yellowing of the plant, specifically younger leaves.

Overwatering or Underwatering

Your tomato plants can also turn yellow if they’re being overwatered or underwatered. Overwatering the plants can deprive them of oxygen and cause root rot, while underwatering can cause the leaves to wilt and turn yellow. It’s important to water your tomato plants consistently and make sure they’re getting enough but not too much water.

Disease or Pest Infestation

A yellowing of tomato plants can also be an indication of disease or pest infestation. Diseases such as Fusarium wilt or Verticillium wilt can cause leaves to turn yellow, and pests like aphids, whiteflies, or spider mites can cause yellowing as well. It’s important to keep an eye on your plants and be vigilant about pests and diseases.

Soil pH

Soil pH is another potential cause of yellowing tomato plants. If the pH of the soil is too high or too low, it can cause nutrient deficiencies in the plant, resulting in yellowing. Tomatoes thrive in soil with a pH between 6.0 and 6.8, so it’s important to test your soil and adjust accordingly if necessary.

Conclusion

There are several potential causes of yellowing tomato plants, including nutrient deficiencies, over- or underwatering, disease or pest infestation, and soil pH. It’s important to be vigilant and take action if you notice yellowing in your tomato plants. By regularly monitoring your plants, you can catch any issues early on and help them thrive.