I started dyeing with acid dyes like most spinners. They're reliable, the colours are predictable, and you can repeat results easily. But after a few years I got curious about natural dyes and started experimenting with what I could find growing around the smallholding.
Natural dyeing is slower and less predictable than synthetic. You won't get the same shade twice. But the colours have a depth and subtlety that I've never achieved with acid dyes. They sit together naturally because they come from the same landscape.
The Basics: Mordanting
Most natural dyes won't stick to protein fibres without a mordant. A mordant is a mineral salt that bonds to the fibre and gives the dye something to attach to. Without it, the colour washes straight out.
I use alum (aluminium potassium sulphate) for almost everything. It's safe, easy to find, and doesn't shift the colour. You dissolve it in hot water, add your yarn, and leave it to soak for at least an hour. I usually mordant overnight.
Mordanting Steps
- Weigh your dry yarn and calculate 10% of that weight in alum
- Dissolve the alum in enough hot water to cover the yarn
- Add the yarn, making sure it's fully submerged
- Heat gently to about 80C and hold for an hour
- Turn off the heat and leave to cool naturally (overnight is fine)
- Remove the yarn, squeeze gently, and it's ready to dye
Dye Plants I Use Regularly
Onion Skins
The easiest starting point. Save the papery outer skins from brown onions. A carrier bag full will dye about 200g of yarn a rich golden-orange. No mordant needed for a reasonable colour, though alum makes it stronger and more lightfast.
Walnut Hulls
The green outer cases of walnuts give a deep, rich brown. I collect them from a tree on the lane in October. They don't need a mordant at all. The tannins in the hull act as their own fixative. I get shades from warm tan through to dark chocolate depending on how long I leave the yarn in.
Weld (Reseda luteola)
Grows wild along field margins here. Weld gives the clearest, brightest yellow of any dye plant I've tried. It's also very lightfast, which is unusual for yellows. I harvest it in July when it's flowering.
Birch Bark and Leaves
Bark gives soft pinkish-browns. The leaves in summer give yellowy-greens that shift to gold with an iron afterbath. I strip bark from fallen branches only.
Elderberry
Berries give a purple-grey that isn't particularly lightfast but is beautiful while it lasts. The colour fades gracefully to a soft mauve over time.
Modifiers
You can shift the colour of a natural dye by adding a modifier after dyeing. This opens up the palette enormously from just a few dye plants.
- Iron (ferrous sulphate): Saddens and darkens the colour. Turns yellows to olive green, tans to grey-brown. Use sparingly or the fibre goes brittle.
- Copper: Shifts colours toward green. Onion skins go from gold to bronze-green. Weld goes from yellow to lime.
- Alkaline shift (soda ash): Pinks and reds from some dyes. Works well with avocado skins and stones.
Tips From Experience
- Keep a dye diary. Write down weights, times, and temperatures. Natural dyeing is unpredictable enough without forgetting what you did.
- Use soft water if you can. Hard water affects some dyes noticeably.
- Don't boil protein fibres. Keep temperatures below 85C or the yarn will felt.
- Natural dyes work best on undyed, light-coloured yarn. BFL and Merino take colour especially well.
- Some dyes improve with age. Let walnut hulls ferment for a week before dyeing for deeper colour.
- Always do a lightfastness test before selling naturally-dyed yarn. Hang a sample in a south-facing window for a month.
Natural dyeing connects you to the landscape in a way that synthetic dyes never can. The colours change with the seasons because the available plants change. Spring gives you fresh greens and yellows. Autumn gives browns and golds. That feels right for yarn that's handspun from local fibre.
If you'd like to try it yourself, I run occasional dye workshops in the warmer months. Get in touch if you're interested.