Can you eat sea lettuce raw?

Yes — shredded raw into salads it is one of the most nutritious greens on the shore, notably rich in protein, iron and vitamin C. Rinse it well in clean water first, as its ruffles hold sand.

What is the difference between sea lettuce and gutweed?

Both are bright green Ulva species, but sea lettuce grows as translucent ruffled sheets while gutweed forms narrow, inflated tubes like tangled green spaghetti, often higher up the shore and in brackish pools. Both are edible; gutweed fries into an excellent crisp.

When is sea lettuce at its best?

It is present all year but at its best size and nutrition through summer and autumn, when sheets can pass 40 cm. Small holes in the blades are just the work of grazing shellfish — nothing to worry about.

Sea Lettuce & Gutweed — Identification & How to Cook Them

By Jayson Byles, forager & chef · Updated August 2026

Sea lettuce (Ulva lactuca) is the shore’s brightest offer: translucent, ruffled sheets of vivid green in the rock pools and along the middle to lower shore, looking exactly like a lettuce leaf gone swimming. Its cousin gutweed (Ulva intestinalis) shares the colour but grows as narrow inflated tubes, and together they are the easy, generous greens every forager starts with.

How do you identify sea lettuce and gutweed?

Sea lettuce is a paper-thin, translucent green sheet, deeply ruffled at the margins, up to 40 cm, held to rock by a tiny disc — hold it to the light and it glows. Gutweed is the same green in tube form: unbranched, slightly inflated strands like green spaghetti, happiest in the upper pools and where fresh water trickles in. Nothing dangerous mimics either; the holes shellfish graze in sea lettuce are a signature, not a flaw.

Hand-drawn identification plate for sea lettuce: bright green, paper-thin ruffled sheet held by a tiny disc — *Sea lettuce* — paper-thin, translucent, deeply ruffled; a tiny disc holds it fast.

Where and when to find them

Rock pools and the mid-to-lower shore all year, at their best through summer and autumn. Both grow fast and regrow faster — cut what you need with scissors and the pool refills the larder within weeks.

How do you cook them?

Sea lettuce keeps its vivid green through heat: shred it raw into salads, whip it into a seaweed butter, roast it as a crisp side, or use whole sheets as wraps — a fish parcelled in sea lettuce for the fire is a staple of On the Rocks. Gutweed, patted dry and flash-fried, shatters into the crisp green garnish chefs pretend is complicated. Both dry well and grind into a green seasoning worth keeping by the stove.

The fastest way to learn a seaweed is to meet it on the rocks with someone who harvests it weekly. Join a workshop on the East Neuk shore — dates and booking here — or take home Jayson’s 52-page e-book Thriving in the Intertidal.

Sea Lettuce & Gutweed

How do you identify sea lettuce and gutweed?

Where and when to find them

How do you cook them?

Notes from the shore