Tomato leaves turning yellow is one of the most common problems UK gardeners face. While it looks worrying, it’s usually easy to fix once you identify the cause.
This guide explains the most common reasons tomato leaves turn yellow and what you can do to save your plants.
Is it normal for tomato leaves to turn yellow?
Sometimes, yes. Older leaves at the bottom of the plant may yellow naturally as the plant grows. However, widespread yellowing usually means something is wrong.
Common causes of yellow tomato leaves
1. Overwatering
Too much water suffocates roots and causes yellow leaves.
- Soil feels constantly wet
- Leaves look soft or limp
2. Underwatering
Dry soil prevents nutrient uptake.
- Leaves curl
- Soil pulls away from pot edges
3. Nitrogen deficiency
Yellowing starts on lower leaves.
4. Magnesium deficiency
Yellow between veins, green veins remain.
5. Lack of sunlight
Tomatoes need at least 6–8 hours of sun daily.
6. Cold weather stress
Chilly nights slow growth.
7. Pests
- Aphids
- Spider mites
- Whitefly
How to fix yellow tomato leaves
Check soil moisture
Water only when the top inch feels dry.
Feed your plants
Use a balanced tomato feed every 10–14 days.
Improve drainage
Add grit or perlite to soil.
Move plants
Ensure full sun exposure.
Remove affected leaves
This improves airflow.
Prevent yellow leaves
- Water consistently
- Feed regularly
- Mulch soil
- Protect from cold snaps
FAQ
Should I remove yellow leaves?
Yes – especially if diseased.
Can tomatoes recover?
Yes, once the cause is fixed.
Are yellow leaves a disease?
Not always – often care-related.
Related guides
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Suggested tags: tomatoes, plant problems, gardening tips
Suggested category: Gardening
