Tomato leaves turning yellow can be caused by several factors including:
- Nutrient deficiencies : Lack of nitrogen is one of the most common causes, resulting in older leaves turning yellow while younger leaves remain green. Deficiencies in magnesium, calcium, and iron can also cause yellowing with specific leaf patterns like green veins on yellow leaves.
- Diseases : Early blight (a fungal disease) often causes yellow leaves with brown spots starting from the bottom leaves. Other diseases like late blight, fusarium wilt, and septoria leaf spot can also cause yellowing.
- Improper watering : Overwatering or underwatering can stress the plant, leading to yellow leaves.
- Lack of sunlight : Tomato plants require at least 6 hours of sunlight daily; insufficient light can cause lower leaves to yellow.
- Pests and environmental stress : Herbicide damage, frost, and pests can also contribute.
To help the tomato plants:
- Check and adjust watering practices to avoid waterlogging or drought.
- Ensure the plants receive enough sunlight.
- Consider fertilizing with nitrogen and micronutrients like magnesium and calcium if deficiencies are suspected.
- Remove yellowing lower leaves if fungal infection like early blight is present, and improve air circulation to reduce humidity.
- Conduct soil testing for precise nutrient requirements.
This combined approach will address the common causes of yellowing tomato leaves and promote healthier plant growth.
