Troubleshooting
Romaine Lettuce problems — and how to fix them
Romaine Lettuce (Lactuca sativa var. longifolia) 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 (above 27°C) and long days trigger seed stalk emergence; leaves become intensely bitter. Grow in spring and autumn; provide afternoon shade in summer; choose slow-bolt varieties such as 'Parris Island Cos'. Harvest promptly before the central stalk begins to elongate.
Lettuce mosaic virus (LMV)
Causes mottled, distorted, or stunted leaves spread by aphids. Use resistant varieties; control aphid populations with insecticidal soap; remove and destroy infected plants. Buy certified virus-free seed where available.
Aphid infestations
Lettuce root aphid (Pemphigus bursarius) and lettuce aphid (Nasonovia ribisnigri) colonise both roots and foliage. Wilting, distorted leaves, or black sooty mould indicate infestations. Use yellow sticky traps, introduce ladybird larvae, or apply neem oil spray. Grow resistant varieties such as 'Little Gem' or 'Chartwell'.
Prevent romaine lettuce problems before they start
Most romaine lettuce issues are care-mismatch, not bad luck. Dial in the basics:
Looking for romaine lettuce in general rather than its problems? Read the full romaine lettuce care guide — light, water, soil and feeding.
Romaine Lettuce problems — FAQ
Why is my romaine lettuce bolting?
Heat (above 27°C) and long days trigger seed stalk emergence; leaves become intensely bitter. Grow in spring and autumn; provide afternoon shade in summer; choose slow-bolt varieties such as 'Parris Island Cos'. Harvest promptly before the central stalk begins to elongate.
Why is my romaine lettuce lettuce mosaic virus (lmv)?
Causes mottled, distorted, or stunted leaves spread by aphids. Use resistant varieties; control aphid populations with insecticidal soap; remove and destroy infected plants. Buy certified virus-free seed where available.
Why is my romaine lettuce aphid infestations?
Lettuce root aphid (Pemphigus bursarius) and lettuce aphid (Nasonovia ribisnigri) colonise both roots and foliage. Wilting, distorted leaves, or black sooty mould indicate infestations. Use yellow sticky traps, introduce ladybird larvae, or apply neem oil spray. Grow resistant varieties such as 'Little Gem' or 'Chartwell'.