Troubleshooting
Iceberg Lettuce problems — and how to fix them
Iceberg Lettuce (Lactuca sativa 'Iceberg') is generally forgiving once you match its basics, but a few issues come up again and again. Here is what each one looks like, why it happens, and the fix.
Failure to form a head
Most commonly caused by heat above 21°C (70°F) or insufficient light. Time sowings so the crop matures in spring or autumn; start indoors in late winter for a spring harvest before summer heat arrives.
Tip burn
Brown, papery inner leaf margins caused by calcium deficiency at the leaf tip due to rapid growth or inconsistent watering. Ensure steady moisture and avoid high nitrogen applications late in development.
Botrytis (grey mould)
Fuzzy grey rot at the base or inside the head, favoured by cool damp conditions and poor airflow. Remove affected outer leaves promptly; avoid overhead watering.
Prevent iceberg lettuce problems before they start
Most iceberg lettuce issues are care-mismatch, not bad luck. Dial in the basics:
- Common lettuce problems — the species this cultivar belongs to
- Common iceberg lettuce problems — our other guide for the same plant
- What's wrong with my plant? — the diagnosis apps compared
- Iceberg Lettuce watering schedule
- Iceberg Lettuce light requirements
- Best soil mix for iceberg lettuce
- Iceberg Lettuce temperature & humidity
- Full iceberg lettuce care guide
Looking for iceberg lettuce in general rather than its problems? Read the full iceberg lettuce care guide — light, water, soil and feeding.
Iceberg Lettuce problems — FAQ
Why is my iceberg lettuce failure to form a head?
Most commonly caused by heat above 21°C (70°F) or insufficient light. Time sowings so the crop matures in spring or autumn; start indoors in late winter for a spring harvest before summer heat arrives.
Why is my iceberg lettuce tip burn?
Brown, papery inner leaf margins caused by calcium deficiency at the leaf tip due to rapid growth or inconsistent watering. Ensure steady moisture and avoid high nitrogen applications late in development.
Why is my iceberg lettuce botrytis (grey mould)?
Fuzzy grey rot at the base or inside the head, favoured by cool damp conditions and poor airflow. Remove affected outer leaves promptly; avoid overhead watering.