Troubleshooting
Iceberg Lettuce problems — and how to fix them
Iceberg Lettuce (Lactuca sativa var. capitata '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.
Bolting
Heat and water stress make it bolt and turn bitter before the head firms, the most common iceberg failure. Grow only in cool spells, keep moisture even, and shade in summer.
Tip burn
Brown, scorched margins inside the head from calcium not reaching fast-growing tissue under heat or uneven watering. Maintain steady moisture and avoid heat stress.
Failure to heart up
Heads stay loose in poor light, warm weather, crowding or excess nitrogen. Space well, grow in cool conditions, and avoid overfeeding.
Rot in the head
Grey mould and bacterial or bottom rot develop in dense, damp hearts. Space plants, ensure airflow, avoid overhead watering, and harvest promptly when firm.
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 bolting?
Heat and water stress make it bolt and turn bitter before the head firms, the most common iceberg failure. Grow only in cool spells, keep moisture even, and shade in summer.
Why is my iceberg lettuce tip burn?
Brown, scorched margins inside the head from calcium not reaching fast-growing tissue under heat or uneven watering. Maintain steady moisture and avoid heat stress.
Why is my iceberg lettuce failure to heart up?
Heads stay loose in poor light, warm weather, crowding or excess nitrogen. Space well, grow in cool conditions, and avoid overfeeding.
Why is my iceberg lettuce rot in the head?
Grey mould and bacterial or bottom rot develop in dense, damp hearts. Space plants, ensure airflow, avoid overhead watering, and harvest promptly when firm.