Why Are My Tomato Plant Leaves Turning Yellow then Brown?

Tomatoes are one of the most popular crops to grow in a home garden, but they can be challenging to care for at times. One of the most common problems that tomato plant owners face is yellow leaves that eventually turn brown. There are several reasons why this could be happening.

Lack of Nutrients

Tomato plants need specific nutrients to grow and thrive, including nitrogen, phosphorus, and potassium. If your plant is lacking in any of these nutrients, it can begin to show signs of stress such as yellowing leaves. To remedy this, fertilize your plant with a balanced fertilizer or compost. Additionally, adding Epsom salt to the soil can help replenish depleted magnesium levels, which can cause yellowing leaves.

Overwatering or Underwatering

Tomato plants require consistent, even moisture to prevent stress. If you are overwatering or underwatering your plant, it may begin to develop yellowing leaves that turn brown. Check the soil frequently to ensure that it is moist but not waterlogged, and adjust your watering schedule accordingly. Additionally, if you are growing your tomato plant in a container, make sure there are drainage holes to prevent water from sitting in the soil.

Pests or Disease

There are several pests and diseases that can cause tomato plant leaves to turn yellow and brown. One common culprit is the tomato hornworm, which can quickly defoliate a plant. Other pests include aphids, spider mites, and whiteflies. If you notice insect damage, use organic methods such as insecticidal soap or neem oil to treat the problem. Diseases such as bacterial canker and leaf spot can also cause yellowing and browning of leaves. If you suspect disease, remove any affected leaves and treat the plant with a fungicide.

Environmental Stress

Tomato plants can also be affected by environmental stressors such as cold temperatures or extreme heat. When exposed to temperatures below 50°F or above 90°F, tomato plants can experience leaf discoloration and other symptoms. Make sure to plant your tomatoes in a location that gets plenty of sun and protection from the elements. Additionally, if you notice that the yellowing and browning is only affecting the leaves on the bottom of the plant, it could be a natural shedding process as the plant redirects nutrients to growing new fruit.

Conclusion

If your tomato plant leaves are turning yellow then brown, it could be due to a variety of factors. By addressing these issues promptly, you can prevent further stress to your plant and ensure a healthy crop. Always remember to properly fertilize, water, and care for your tomato plant to keep it thriving.