Introduction

Tomatoes are one of the most widely grown vegetables in home gardens and the commercial farming industry. One critical aspect of tomato plant care is ensuring they grow healthy green leaves. Tomatoes with yellow leaves tend to indicate a sickly or dying plant. If you're encountering yellow leaves on your tomato plants and wondering "why there are leaves on tomato plants turning yellow?" keep reading below.

Plant Disease

Plant diseases are common causes of yellowing tomato leaves, and it's crucial to identify them early on to prevent further damage. Some of the most common plant diseases that cause yellow leaves on tomato plants include the Early Blight disease, the Late Blight, the Fusarium Wilt, and the Bacterial Speck.

Early Blight causes dark, concentric rings on the tomato plant leaves, while Late Blight rusts the plant and causes crispy, dry leaves. Fusarium Wilt causes yellowing of the leaves from the bottom upwards, with yellowed leaves dropping off. Bacterial Speck causes small, circular yellow spots on the tomato leaves, with the presence of black specks in the middles.

Nutrient Deficiency

Yellow leaves on tomato plants could be an indicator of Nitrogen, Potassium, or Iron deficiency. Nitrogen is essential in the formation of chlorophyll; lack of it causes yellow leaves. Potassium deficiency causes yellowing of the edges of lower leaves, while Iron deficiency causes yellowing of the leaves with green veins.

To remedy Nutrient deficiencies, fertilizers rich in Nitrogen, Potassium, or Iron can be applied.

Improper Irrigation

Imbalanced watering, whether too much or too little, can cause yellow leaves on tomato plants. Overwatering causes root rot, hence causing yellow leaves, while underwatering causes the plant to stress, leading to yellowing of leaves.

To correct improper irrigation, set a watering schedule and stick to it, ensuring that the plant receives adequate water, but not drowning it.

Pests Infestation

Tomato plants are vulnerable to several pests, including aphids, whiteflies, spider mites, and tomato fruit worms. Pests infestation causes damage to the leaves, developing yellow dots or streaks.

To manage pests infestation, consider using natural methods, such as bug repellent plants or organic insecticides.

Conclusion

There are several reasons why leaves on tomato plants turn yellow, including nutrient deficiency, plant diseases, pests infestation, and improper irrigation. As an avid gardener or farmer, it's essential to observe the signs of yellowing leaves and identify the root cause. Correctly managing your tomato plant care will lead to healthy green leaves, abundant produce, and a bumper crop at harvest-time.