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  • Writer's pictureSarah Matthess

Coastal Colours - dye wool with seaweed!

Updated: Jun 22, 2020

Any natural plant dyer is constantly on the look out for new colours, whether from seeds, nuts, bark, leaves, plants, lichen, fungi, you name it, we try it out don't we? Any time there's a 'glut' in the garden, onion skins, carrot tops, red cabbage, we can't just throw it on the compost without first trying to obtain a colour from it.

Beach combing is a habit for me, because I'm not too far from a coast line. I had seen some dye-experiments with seaweed online, so I thought I would give it a try.

Definitely it's worth washing the seaweed off in the surf if that's possible for two reasons...

One is the local dog population, the other is any little beachy insects that are in there will not survive being hosed down on the patio with fresh water. But after bringing home my sack of seaweed, I spread it out to give it a good hose down.

I wasn't too scientific about this process of collecting because the storms throw up all kinds of seaweed in heaps which are a tangled mess. But for the most part, the bundle I collected looked like this...

My experience with most natural plant dyeing is that it takes a lot of plant material to produce a decent colour on wool, so I stuffed the entire bundle (it filled about half a plastic fertilizer sack) of seaweed into my largest stainless steel stock pot. Most plant-dye-pots give off unusual aromas. Seaweed is no exception. Have to say the house was pretty stinky after bringing it to a gentle simmer, even with the extractor fan on.

I pre-mordanted this Shetland fibre in a solution of 8% alum, and 5% cream of tartar.

Then straining off the fluid from the seaweed dye-bath, I immersed the already wet fibre into the seaweed fluid.

I always strain my dye-baths outside to avoid spills running all over my floor, and I do it through a large sieve into a plastic bucket, then return it to the original dye-pot.

The remaining cooked seaweed went straight onto the compost dome when cooled. It looks like it's steaming hot here, but actually it was just a very cold day that made it look steamy.

Seaweed nutrients are not very high in nitrogen apparently, but they do contain about 60 other trace elements that will feed your soil. There's a lot of information on the internet about seaweed as a fertiliser/compost. It improves the soil and helps sandy soil to retain moisture. As it's entirely free, this is a valuable resource, and in the past it was used extensively in family potato production in Ireland.

After gently simmering my Shetland fibre for about an hour, I strained off the remaining fluid, rinsed the fibre and spun it out in my top loader spin dryer. There was a lot of dye left in the remaining liquid.

I experimented with the liquid to see if I could push the colours more into the pink-range with a few drops of ammonia, and I have to say it did make a slight difference to the finished colour, although not a lot, but I was after pinky-flesh tones and I felt pretty happy with the result.

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