The colour in most of your wardrobe came from a petrochemical plant. The colour in some of your wardrobe could come from your green bin. This is a guide to the second one.
Why bother?
Natural dyeing has three honest virtues: it's beautiful, it's almost-free, and it gives a second life to garments you'd otherwise replace. There's a fourth virtue, less practical — the act of dyeing reconnects you to clothing as a made thing. Industrial dyes hide their origins. Plant dyes don't.
This guide covers three of the most reliable beginner dyes: avocado pits, yellow onion skins, and pomegranate rind. All three are food waste. All three give strong, repeatable colour on cotton and silk with minimal kit. Once you've done one, you've done them all.
The kitchen palette
Here's what you can expect on natural fibre (cotton, linen, silk, wool) when each dye is properly mordanted. Synthetics will not take plant dye reliably — don't waste the time.
Iron after-baths are the cheat code — they don't just deepen the colour, they shift the whole hue cooler. The same dyebath gives you two distinct colours depending on whether you finish with iron.
What you need
Almost everything in your kitchen will do. The only rule: anything you use for dyeing should not later be used for food. Buy second-hand stainless-steel pots; charity shops have piles of them.
- A large stainless-steel or enamel pot (4–8L). Not aluminium — it shifts the colour unpredictably.
- A wooden stick or stainless spoon for stirring.
- Tongs or rubber gloves.
- A muslin bag or fine sieve.
- A jam jar.
- A scale that goes to 0.1g (a coffee scale is fine).
- Alum (potassium aluminium sulphate) for mordanting — pickling-grade is fine.
- A small jar of iron sulphate (ferrous sulphate) for after-baths. Garden centres sell it as a lawn moss-killer; check it's "ferrous sulphate" only.
Mordanting (do this first)
A mordant is a metal salt that bonds the dye to the fibre. Without it, plant dyes mostly wash out within a few launderings. With it, they last for years.
Alum mordant — cotton & linen
For 100g dry fabric:
- 15g alum dissolved in 5L hot water
- Add wet, scoured fabric (washed plain, no detergent residue)
- Bring to a low simmer (80°C); hold 1 hour
- Turn off heat; let fabric cool in the bath overnight
- Wring out (don't rinse). Mordanted fabric can be used now or dried and stored for later.
Alum mordant — silk & wool
Same as above but use 8g alum per 100g fibre, and never let wool experience temperature shocks (it'll felt). Bring to temperature gradually, cool gradually.
Recipe — Avocado pink
The most magical of the three. Avocado pits look brown; the dye is a delicate shell pink. Save your pits in the freezer for two weeks before dyeing — six pits will dye 100g of fabric.
Avocado on cotton — pink
- Crush 6 frozen avocado pits with a hammer (in a tea towel, on a hard floor).
- Cover with 4L water in your dye pot. Simmer at 80°C for 1 hour.
- Strain out the pit fragments. The liquid will be a deep magenta.
- Add wet, alum-mordanted cotton. Simmer at 60°C for 45 minutes, stirring occasionally.
- Turn off heat; let cool in the pot for 4–24 hours. The longer it sits, the deeper the pink.
- Rinse in cold water until water runs clear. Hang to dry out of direct sun.
Recipe — Onion gold
The most reliable. Yellow onion skins are abundant (ask your greengrocer; they bag them up for free), the colour is fast, and you'll get gold from the first attempt. This is the recipe to start with if you've never dyed before.
Onion skin on cotton — gold
- Collect 50g (a generous handful) of dry yellow onion skins.
- Soak skins overnight in 4L cold water.
- The next day, simmer the soak at 90°C for 45 minutes. Liquid will turn deep amber.
- Strain out the skins.
- Add wet, alum-mordanted cotton. Simmer at 70°C for 1 hour.
- Turn off heat; let cool in the pot for 2 hours.
- Rinse, hang dry.
After dyeing, dip the rinsed fabric into a 0.5g/L iron sulphate solution for 5 minutes. The gold will shift to deep bronze almost instantly. Rinse thoroughly afterwards or the iron will degrade the fabric over time.
Recipe — Pomegranate khaki
The most surprising. Pomegranate rind looks like it should give pink — it gives a beautiful soft khaki on cotton and a deep olive on wool. Tannin-rich, so it acts as its own partial mordant; the colour is very wash-fast.
Pomegranate on cotton — khaki
- Save the rind from 4 pomegranates. Dry on a windowsill until brittle (or use fresh — it works either way).
- Roughly tear or crush, then soak overnight in 4L water.
- Simmer at 90°C for 1 hour.
- Strain.
- Add wet, alum-mordanted cotton. Simmer at 70°C for 1 hour. Cool overnight.
- Rinse, dry out of direct sun (UV will fade pomegranate faster than the others).
Care & fixing
Three things will make your plant-dyed pieces last:
- Wash cold, infrequently. Most modern garments are over-washed by a factor of three. Plant-dyed pieces especially.
- Use pH-neutral soap. Avoid alkaline detergents (most laundry powders are alkaline) — they shift colour, especially with avocado.
- Dry out of direct sun. All natural dyes are more UV-sensitive than synthetics. Indoor drying or shaded line is best.
Iron sulphate is a fertiliser at low concentration and a skin irritant at higher ones — wear gloves. Never use a copper pot for dyeing without research; copper is its own mordant and it changes everything. Stick to stainless or enamel.
Live workshops
If reading recipes isn't your thing, our Roots to Renewal programme runs in-person workshops in Doncaster every season. We provide the kit, the fibres, the food waste, and the patience. You bring a t-shirt to dye and an open mind.
Bookings and the workshop schedule are at rootstorenewal.co.uk. Schools, community groups and corporate sustainability days are welcome — get in touch via our contact page.