Sea Lettuce
Ulva lactuca
Also known as: Sea Lettuce, Green Laver, Green Nori
'Ulva' is Latin for 'marsh plant' or 'sedge'. 'Lactuca' is Latin for 'lettuce', an apt description of the bright green, flat, translucent, lettuce-like fronds. Sea lettuce has been eaten across Europe, Asia, and the Pacific for centuries – in Ireland and Wales as 'laver', in Japan as 'aosa'. Ulva lactuca is a bright, vivid-green seaweed found in intertidal rock pools, rocky shores, and shallow subtidal zones around much of the temperate Australian coast. It grows as flat, translucent, ruffled sheets, typically 10–30 cm across, attached to rocks by a small holdfast or lying free in pools. One of the most edible, nutritious, and mild-flavoured seaweeds in the world.
When to Forage
Year-round; most abundant in spring and summer.
Cautions
Moderate iodine content – see the Iodine Note above. Blanch before eating if consuming regularly. Avoid collecting from areas near sewage outfalls, industrial facilities, or stormwater drains. Sea lettuce in high-nutrient, polluted water can accumulate heavy metals and bacterial pathogens. If you see warning signs at a beach, do not collect.
Nutrition
High protein content for a plant (up to 20% dry weight); high in iron, calcium, magnesium, potassium, iodine, and manganese. Contains vitamins C, B12 (small amounts), and A. Rich in ulvan – a sulphated polysaccharide with anti-inflammatory and gut-health benefits. Very low in calories.
How to Identify
- Brilliant, vivid green, flat, sheet-like fronds that are thin, almost translucent, and slightly ruffled or wavy at the margins.
- Texture is smooth and slightly slimy when wet, drying to a papery, dark green sheet.
- Attached to rock by a small, disc-like holdfast – when free-floating, drifts in sheets in pools.
- Fronds are two cell layers thick – very thin and translucent when held to light.
Lookalikes
Closely related, with tubular fronds rather than flat sheets – see separate entry.
Multiple Ulva species exist, all edible with the same iodine caveats.
How to Forage
Pick fresh, brightly coloured fronds directly from rock surfaces at low tide. Avoid pale, white, or yellow fronds (dying material). Rinse thoroughly multiple times to remove sand, grit, and small invertebrates. Blanch briefly before use. Can also be dried in the sun for later use.
Recipe — Sea Lettuce Fritters
Ingredients: 2 large handfuls fresh sea lettuce, blanched and roughly chopped; 1 cup plain flour; 2 tbsp ground flaxseed mixed with 5 tbsp water (flax egg); 150 ml cold sparkling water; 1/2 tsp salt; 1/4 tsp white pepper; pinch of dried chilli; oil for frying; soy sauce or tahini to dip. Method: Blanch the sea lettuce in boiling water for 30 seconds, drain, refresh in cold water, and squeeze out excess moisture, then roughly chop. Prepare the flax egg by mixing the ground flaxseed with water and letting it sit for 5 minutes until thickened. Whisk the flour, flax egg, and sparkling water into a light batter, and season with salt, pepper, and chilli. Fold in the sea lettuce. Heat 1–2 cm of oil in a pan over medium-high heat. Drop spoonfuls of batter into the hot oil and fry for 2 minutes per side until golden. Drain on paper towel and serve with soy sauce or tahini. Inspo: sea lettuce furikake – add sea lettuce into your seaweed mix in the recipe.
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