Why Your Tomato Leaves Are Turning Yellow and How to Fix It - No Plant No Life

Wednesday, July 3, 2024

Why Your Tomato Leaves Are Turning Yellow and How to Fix It

Tomato plants, with their lush green foliage and vibrant red fruits, are a staple in many gardens. 

However, a common issue that gardeners face is the yellowing of tomato plant leaves. 

This can be a sign of several underlying problems, ranging from nutrient deficiencies to pest infestations. 

In this comprehensive guide, we'll explore the various reasons why your tomato plant leaves might be turning yellow and provide step-by-step instructions on how to address each issue.

Common Causes of Yellow Leaves in Tomato Plants

🔹Nutrient Deficiencies

🔹Watering Issues

🔹Soil pH Imbalance

🔹Pests and Diseases

🔹Environmental Stress

🔹Improper Pruning

🔹Transplant Shock

1. Nutrient Deficiencies

Nitrogen Deficiency


1️⃣ Yellowing of the older leaves at the base of the plant.

2️⃣ Overall stunted growth and pale green color of the plant.


1. Test the Soil: Use a soil testing kit to check the nitrogen levels in your soil.

2. Add Nitrogen Fertilizer: If the soil is deficient in nitrogen, add a balanced fertilizer with a higher nitrogen content, such as a 10-5-5 ratio.

3. Use Organic Amendments: Incorporate organic matter such as compost or well-rotted manure into the soil to improve nitrogen availability.

4. Regular Feeding: Continue to feed your tomato plants with a balanced fertilizer every 2-4 weeks during the growing season.

✅ Magnesium Deficiency


1️⃣ Interveinal chlorosis (yellowing between the veins) on older leaves.

2️⃣ Leaves may curl and develop brown spots.


1. Epsom Salt Solution: Dissolve 1 tablespoon of Epsom salt in a gallon of water and apply it to the soil around the base of the plant.

Repeat every two weeks until the symptoms improve.

2. Soil Amendment: Add a magnesium-rich amendment, such as dolomitic lime, to the soil according to the package instructions.

2. Watering Issues



1️⃣ Yellowing of the lower leaves.

2️⃣ Wilting of the plant despite wet soil.

3️⃣ Root rot in severe cases.


1. Check Soil Moisture: Stick your finger about an inch into the soil. If it feels wet, wait to water until it feels dry to the touch.

2. Improve Drainage: Ensure that your tomato plants are in well-draining soil. If necessary, amend the soil with sand or perlite to improve drainage.

3. Watering Schedule: Water your tomato plants deeply but infrequently, allowing the soil to dry out between waterings.



1️⃣ Yellowing and wilting of the lower leaves.

2️⃣ Dry, brittle leaves.


1. Consistent Watering: Water your tomato plants regularly, ensuring that the soil remains consistently moist but not waterlogged.

2. Mulching:
Apply a layer of mulch around the base of the plants to help retain soil moisture and reduce evaporation.

3. Soil pH Imbalance


1️⃣ General yellowing of the leaves, often starting at the edges.

2️⃣ Poor growth and reduced fruit production.


1. Test Soil pH: Use a soil pH testing kit to determine the pH level of your soil. Tomato plants prefer a pH between 6.0 and 6.8.

2. Adjust pH: If the soil is too acidic (pH below 6.0), add lime according to the package instructions to raise the pH.

If the soil is too alkaline (pH above 6.8), add sulfur or peat moss to lower the pH.

3. Retest Soil: After making amendments, retest the soil pH to ensure it is within the optimal range.

4. Pests and Diseases



1️⃣ Yellowing and curling of leaves.

2️⃣ Sticky residue (honeydew) on the leaves and stems.

3️⃣ Presence of small, pear-shaped insects.


1. Manual Removal: Spray the plants with a strong jet of water to dislodge the aphids.

2. Neem Oil: Apply neem oil or insecticidal soap to the affected plants, following the label instructions.

3. Introduce Beneficial Insects: Encourage or introduce natural predators such as ladybugs and lacewings into your garden.

✅ Fungal Diseases


1️⃣ Yellow spots or patches on the leaves.

2️⃣ Wilting and browning of leaves.

3️⃣ Presence of fungal spores or mold.


1. Remove Infected Leaves: Prune and dispose of any infected leaves to prevent the spread of the disease.

2. Fungicide Application: Apply a fungicide labeled for use on tomatoes, following the manufacturer's instructions.

3. Improve Air Circulation: Space plants appropriately and avoid overhead watering to reduce humidity around the plants.

5. Environmental Stress

Temperature Extremes


1️⃣ Yellowing and wilting of leaves.

2️⃣ Reduced fruit set and growth.


1. Shade Cloth: Use shade cloth to protect plants from excessive heat during the hottest part of the day.

2. Row Covers: Use row covers to protect plants from cold temperatures and frost.

3. Optimal Planting Time: Plant tomatoes at the appropriate time for your region to avoid temperature extremes.

Wind Damage


1️⃣ Yellowing and browning of leaves, especially at the edges.

2️⃣ Broken or damaged stems.


1. Windbreaks: Use windbreaks or barriers to protect plants from strong winds.

2. Staking: Stake or cage your tomato plants to provide support and reduce wind damage.

6. Improper Pruning


1️⃣ Yellowing of leaves due to stress.

2️⃣ Reduced plant vigor and productivity.


1. Prune Correctly: Prune tomato plants carefully, removing only the suckers and lower leaves that touch the ground.

2. Sanitize Tools: Always use clean, sanitized pruning tools to prevent the spread of disease.

7. Transplant Shock


1️⃣ Yellowing of leaves after transplanting.

2️⃣ Wilting and stunted growth.


1. Acclimate Plants: Gradually acclimate seedlings to outdoor conditions before transplanting them into the garden.

2. Water Well: Water the plants thoroughly before and after transplanting to reduce shock.

3. Use Root Stimulators: Apply a root stimulator or transplant fertilizer to help the plants establish quickly.


Yellowing leaves on your tomato plants can be a sign of various issues, but with careful observation and appropriate interventions, most problems can be resolved. 

Regularly inspect your plants for signs of nutrient deficiencies, watering issues, pests, diseases, and environmental stress. 

By providing your tomato plants with the right care and addressing issues promptly, you can ensure a healthy and bountiful harvest. Happy gardening!


What is the most common cause of yellow leaves on tomato plants?

Nutrient deficiencies, particularly nitrogen deficiency, are often the most common cause of yellowing leaves on tomato plants.

How often should I water my tomato plants to prevent yellow leaves?

Water deeply but infrequently, allowing the soil to dry out between waterings. Typically, this means watering every 2-3 days.

Can yellow leaves on tomato plants recover and turn green again?

Yes, if the underlying issue, such as nutrient deficiency or watering problem, is corrected promptly, new growth will be healthy and green.

How can I tell if my tomato plants are overwatered or underwatered?

Overwatered plants will have yellowing lower leaves and wet soil, while underwatered plants will have dry, brittle leaves and dry soil.

Should I remove yellow leaves from my tomato plants?

Yes, remove yellow leaves to prevent potential disease spread and allow the plant to focus its energy on healthy growth.

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