How to use seaweed in the garden - Halen Môn

How to use seaweed in the garden

by | Apr 18, 2024

As far as we’re concerned, seaweed is a magical ingredient. Not only can it work wonders for your skin, with deeply moisturising properties, but in coastal areas,  it’s been used as a soil improver for generations.

Seaweed contains lots of useful plant nutrients, including nitrogen, potassium, phosphate and magnesium. There are plenty of dried and liquid forms available from garden centres. 

If you find yourself somewhere beachy, you can collect seaweed after particularly stormy weather (don’t collect living seaweed, attached to rocks etc, it’s not sustainable for everyone to do so.)

How can you unleash seaweed’s natural powers in your garden, we hear you ask? 

Grow the best tomatoes in town

Tomatoes are well-known for being hungry crops and thrive on the minerals found naturally in seaweed. Some enthusiastic gardeners also report a difference in tomato taste.

Use dead seaweed as a mulch


If you’re lucky enough to have had a Wild Seaweed Bath with us here in Brynsiencyn, or bought one to do yourself at home, save your seaweed afterwards and use it as a mulch (pop it around plants on top of the soil). Mulching is generally used to save water, suppress weeds and improve the soil around plants. Slugs don’t like seaweed!

Enrich your compost

Add the seaweed to your compost, or compost it on its own. As seaweed breaks down into the soil, it encourages microorganisms whose activities help convert unavailable nutrients into forms that plants can use. Once broken down, it’s the secret ingredient for growing thin-skinned new potatoes. 

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