What nutrient deficiency causes leaf curl?
Written by
Kiana Okafor
Reviewed by
Prof. Charles Hartman, Ph.D.In tomatoes, leaf curl most likely indicates a nutrient deficiency rather than a virus infection. A potassium deficiency results in upward leaf curl and scorched leaf edges. A magnesium deficiency results in yellowing between the veins of older leaves. A calcium deficiency will result in abnormal growth of new tissue, along with black or dead spots. While viral curl will not recover, these problems will recover once corrected.
Potassium Issues
- Symptoms: Upward curling with brown scorch marks on leaf margins
- Soil test: Confirm when levels drop below 150 ppm
- Correction: Apply potassium sulfate at 1 tbsp per plant weekly
Magnesium Shortage
- Symptoms: Yellowing between veins on mature leaves downward curling
- Soil test: Identify below 50 ppm magnesium levels
- Correction: Use Epsom salt solution 1 tbsp per gallon biweekly
Calcium Deficiency
- Symptoms: Distorted new growth with necrotic spots blossom end rot
- Soil test: Detect below 1000 ppm calcium
- Correction: Apply gypsum at 4 oz per plant monthly
Nutrient issues are more general across the plants than location-specific viral infections. All nutrient deficiencies, on the other hand, develop over a period of weeks while viral symptoms arise quickly. Soil testing can give a confident yes or no. I perform soil tests each spring to avoid these issues before planting.
To correct deficiencies, we can utilize targeted amendments. Foliar amendments are the quickest way to add nutrients because they put nutrients right on the leaf. Soil amendments can provide long-term answers. Maintain soil pH levels between 6.0 and 6.8 to maximize nutrient availability. I often combine compost and mineral amendments for balanced nutrition.
Avoid deficiencies by conducting routine soil testing and applying balanced fertilization. Use complete fertilizers that include micronutrients. Prevent over-watering that drains nutrients from the soil. Be sure to observe your plants on a weekly schedule during times of vigorous growth. Healthy, grown tomatoes are more resistant to nutrient deficiencies and diseases.
Read the full article: Tomato Leaf Curl Virus: Complete Guide
