Why Garden Plants Make Wonderful Dyes

There is something quietly magical about dyeing yarn with things you would otherwise compost. A bag of onion skins, a handful of marigolds past their best, a spring crop of nettles — all of them hold colour that bonds beautifully to wool, silk and alpaca. The shades are rarely neon; they are soft, shifting and full of depth, the sort of colours that sit happily side by side in a striped shawl or a Fair Isle yoke. Results vary with water, fibre and even the weather, and that variation is part of the pleasure. Keep notes and you will build a personal palette no dyehouse could replicate.

Be realistic about light fastness, though. Plant dyes fade more readily than synthetic ones, so store finished skeins away from direct sunlight and accept that a jumper will soften over years of wear. That softening is often rather lovely.

Preparing Fibre and Choosing a Mordant

Dye will not cling reliably to greasy wool. Scour first: soak your skeins in warm water with a little pH-neutral wool wash for 30 minutes at around 60°C, then rinse gently. Tie each skein loosely in at least four places so it cannot tangle in the pot.

A mordant — usually a metal salt — helps the dye bond to the fibre. For 100g of dry yarn, the classic recipe is 10g alum plus 5g cream of tartar. Dissolve both in hot water in a dedicated pot, top up with enough water to cover the fibre, add the wet skeins, and raise the temperature slowly to 80–85°C. Hold for an hour, then let everything cool overnight in the bath. Rinse well before dyeing.

Safety matters here.

• Keep dye and mordant pots, spoons and jugs strictly separate from kitchen equipment, and label them clearly.
• Wear gloves and work in a well-ventilated space, ideally outdoors or in a garage.
• Never let mordant powders become airborne; dissolve them in water before adding fibre.
• Store mordants out of reach of children and pets, and dispose of spent baths responsibly.

Onion Skins: Reliable Golds and Coppers

Onion skins are the perfect first dye. They are free, need no special handling, and give dependable warm golds on wool. Yellow and brown skins lean towards honey and amber, while the papery skins of red onions give a softer apricot-bronze. Collect them in a paper bag and keep them dry until you have around 100g — roughly the same weight as your dry fibre.

Simmer the skins in plenty of water for 40 minutes, then strain. Return the clear liquid to the pot, add your mordanted, wet skeins, and hold at 80°C for an hour. Stir gently and infrequently. For a deeper, more orange tone, add a pinch of soda ash to the bath; for olive and brown, lift the skeins out and dip them briefly in a weak iron bath made from ferrous sulphate.

Marigolds: Sunshine in a Pot

French and African marigolds, and calendula too, are generous dye plants. Deadhead regularly through summer and dry the flowers on a tray in a warm, airy spot. Use 100–200g of dried flowers per 100g of fibre; fresh blooms need roughly triple that. Simmer the flowers for 30 minutes, strain, and dye as above.

On alum-mordanted wool you can expect clear yellows through to deep gold. A brief iron dip turns them olive, while a little soda ash brightens them towards lemon. Calendula tends to be softer and more buttery than tagetes.

Nettles: Soft Greens and Sage

Nettles are best picked in spring, before they flower, from a clean spot away from roads and popular dog-walking routes. Wear thick gloves and take only the top few leaves. Use 200–300g of fresh nettle tops per 100g of fibre, or about 100g dried.

Chop the leaves roughly and simmer gently for an hour to extract the colour. Strain, then dye mordanted fibre for 45–60 minutes. Nettles on alum alone give delicate yellow-greens and pale sage; add a small amount of iron and the colour deepens into a rich, moody green. Nettle root, dug in autumn, yields soft yellows if you fancy experimenting.

Keeping Notes and Caring for Dyed Yarn

Record everything in a notebook: fibre weight, mordant and percentage, dyestuff weight, water source, temperature, timings, and any modifiers used. Tape a small sample of the finished yarn beside the notes. Without this, repeating a colour you love becomes guesswork.

Wash finished skeins in cool water with a pH-neutral wool wash, rinse until the water runs clear, and dry them in the shade. Expect a little colour to release in the first wash or two. Store skeins away from direct sunlight, and enjoy the way your garden slowly becomes a dyepot.