Natural dyeing with onion skins

Many moons ago I recorded a podcast episode devoted to natural dyeing and anticipated that I’d be writing a blog post natural dyeing with onion skins at home much sooner than this. But, life (and work) happens so here we are after a bit of a pause. I’m just getting ready to record another podcast to talk about my adventures in ecoprinting, so keep a look out for a new release on my YouTube channel in the next few days.

I talked a lot about natural dyeing with onion skins and other plant materials in Episode 52 of the podcast – check out the podcast notes and a link to the video if you’ve not watched it.

If you want to start doing some dyeing at home, natural dyeing with onion skins is a good first project. Onions are pretty easy to get hold of and as you can eat the onions and just use the waste, its low cost. You don’t need any special equipment or expensive chemicals. Onion skins also give really strong colours, even with a relatively small amount of plant material and without the use of even an alum mordant.

Natural dyeing with onion skins – what you need

• An old pan – I got three from a car boot sale for £1. Or ask around for someone who is replacing their pans and throwing some old ones out.
• Onion skins. I used the skins from about 10 onions and I dyed about 75g of wool. If you want to be more scientific about it, weight the wool dry and use that weight again of onion skins for a really strong colour. Save your onion skins in a freezer bag and freeze every time you cook until you have enough.
• Cold water – enough to cover the onion skins. Its good to have at least 1 litre of liquid left at the end, so start with 1.5 litres if possible.
• An old sieve and some muslin (or old tights).
• A skein of undyed wool, or any other natural fibre.

Onion skins dye wool really well without a mordant. This is a chemical used to make the wool more receptive to taking up the natural pigments. You can use a mordant if you want – I used alum (aluminium sulphate) which is used as a food preservative so is pretty safe, even if you are dyeing in your kitchen.

Precautions when natural dyeing

This doesn’t really come into it very much when you are dyeing with onion skins but if you want to dye with other plant materials and use other mordants or modifiers such as iron sulphate or copper sulphate, you have to use some sensible precautions:

• Wear gloves – household gloves are fine as long as you wash your hands while wearing them once you are done dyeing. Or buy disposables.
• Use pans and utensils that are just kept for natural dyeing. Don’t use them to prepare food afterwards.
• Use a dust mask if you are measuring out or using any sort of powder or fine crystals.
• Make sure you work on a wipeable surface – buy a cheap plastic tablecloth to cover your preparation area.
• Take care when moving pans with boiling liquid and leave them out of reach of little fingers and pets paws.
• Never leave your dyepot unattended while heating or let it dry out on the heat.
• Don’t eat or drink or smoke while you are experimenting with natural dyes. Transferring stuff to your mouth is a bad idea.
• Don’t assume that just because you are dyeing with a plant from your garden that its safe. Many plants are poisonous and should be treated with respect.

Preparing the onion skin dye extract

Collect together your fresh or frozen onion skins and put them in the pan and cover with water. You can use just red onion skins, just brown, or a mixture of both. Put the pan on to heat on your regular stove or a separate electric ring. I use the ones you can buy for caravans and if you use the correct extension lead (make sure you don’t overload the socket) you can even set up your dyepot outside on a nice summer’s day.

Bring to the boil then simmer for about 2 hours. Leave covered with the lid to cool completely. You can easily leave it overnight and then strain it the next morning.

Stretch the muslin or the tights over the sieve and fix in place with a rubber band. Work in a sink and pour the extract through the sieve into a container for your dye extract. I just use a plastic measuring jug that takes 3 litres so I can rinse the pan out ready for dyeing. Its best to use the extract as fresh as possible but you can put it in a sealed container in the fridge overnight for dyeing the next day if you need to.

The extract should be a lovely deep orange to red colour but it does depend on the type of onions you use and how many skins are boiled. As you can see, the colour of the extract does not match the colour of the wool once its dyed:

Dyeing wool with onion skins

• Soak the skein of undyed wool in water (or water with a teaspoon of alum added) and leave for at least one hour to make sure the wool is fully wetted.
• Squeeze out gently so the skein isn’t sopping but don’t squeeze or wring it out too tight as it might stretch and damage the wool, which becomes quite fragile when its wet.
• Put your fresh extract into the dyepot or pan and lower in the wetted wool. Allow it to soak in there for about 10 minutes then heat up slowly until the liquid simmers and bubbles gently.
• Its not a good idea to let it boil furiously as this can felt the wool.
• Keep it at simmering point for about 30 minutes then turn off the heat and allow the dyepot to cool completely.
• Put on your gloves and remove the skein for washing. There will be a lot of excess dye so be careful where you drip!
• Rinse the skein under running cool water in the sink to get more of the excess dye off then put some water in the skin for washing the skein. I use either ordinary washing up liquid or baby shampoo for natural dyeing experiments. A couple of washes and rinses might be needed until the water runs clear.
• Hang your skein up to dry. For quicker drying, put it through a spin drier or salad spinner first. Drying a full 100g skein, even one that has been spun dried, takes about 24 hours. Don’t be tempted to dry it in the sun to speed things up – that carries the risk of fading the natural dye that you’ve just worked hard to get into the wool.

Using iron and copper modifiers with onion skin dyed wool

Salts of iron and copper have long been used to deepen and soften the colours of natural dyed yarn and fabric. I’ve only just started using these but I did experiment with some of the yarn I’d dyed with red onion skin extract and brown onion skin extract. After the skeins had been dyed, I placed them into a fresh dyepot with a litre of water and half a small scoop of either iron sulphate or copper sulphate, brought them to simmering point and then allowed them to cool overnight.

In very small amounts and when used with care, these modifiers can help create more colours from natural dyes but they do sort of go against the grain of using just natural plant materials so I’ve still not really decided how much of them I will use in the future.