SEA LETTUCE - GREEN SEAWEED
Sea lettuce (Ulva lactuca) is a bright green seaweed found on rocky shores worldwide, including all around the British coast. It grows in thin translucent sheets that genuinely do look like lettuce leaves, and it's the mildest of the common British seaweeds — which makes it the easiest place to start if you've never cooked with seaweed before.
What It Looks Like
Sea lettuce grows in loose, ruffled sheets, usually a few centimetres across but sometimes reaching 30cm or more. It's only two cells thick, so it's translucent when held up to the light and tears easily.
You'll find it in rock pools and on the middle and lower shore, attached to rock by a small holdfast — though it's also common as free-floating material in sheltered bays. It's abundant, easy to identify, and hard to confuse with anything harmful.
What It Tastes Like
Mild, fresh and lightly briny — closer to a salad leaf than to the strong savoury depth of the kelps. There's a faint grassy quality and a clean saltiness, but it doesn't dominate a dish.
The texture is thin and slightly slippery raw, and it crisps well when fried or dried.
How to Use It
- Raw in salads — rinsed thoroughly, torn into pieces, dressed simply. Good with citrus, cucumber and a light oil.
- Fried until crisp — dried first, then flash-fried. Similar to the "crispy seaweed" served in Chinese restaurants, though that's usually cabbage.
- Dried and crumbled — as a finishing seasoning over rice, potatoes or eggs, in the same way aonori is used.
- In soups and broths — added in the last minute, off the heat, so it keeps its colour.
- As a wrap — larger sheets can hold rice and vegetables, though it's more fragile than nori and needs handling gently.
Where It Grows, and a Word of Caution
Sea lettuce is a nitrogen-loving seaweed, and it thrives where nutrient levels are high. That means it's abundant in exactly the places you shouldn't harvest from — near sewage outfalls, agricultural run-off and enclosed harbours, where it can form thick green blooms.
Pick from clean, open coast with good water movement. If a bay is carpeted with it and the water is still, that's a signal rather than a bounty.
Harvesting
Cut with scissors and leave the holdfast so the plant regrows. Take from the growing plant rather than the strandline — sea lettuce is thin and decomposes fast once detached. Take a small proportion of what's there and rinse well in fresh water before use.
Nutrition
Sea lettuce contains vitamins A and C, B vitamins, iron, iodine and calcium, along with dietary fibre and a relatively high protein content for a seaweed. Iodine levels are considerably lower than in the kelps.
Related
Sea lettuce is one of the green seaweeds, alongside gutweed and aonori. See our guide to edible seaweed in the UK for what else grows on the same shore, or the full guide to edible seaweed.
Seaweed has been a source of savoury flavour for centuries. Sozyë's sauces are brewed from a blend of wild Scottish seaweeds, harvested off the north coast of Scotland.