Knowing your Onions

with Fran Rushworth

Onion Skin Dyes on Wool, Cotton and Silk

Fran Rushworth grows dye plants in her garden in Bridgend and sells plant dyed items in the shop ‘Crafts by the Sea’ in Ogmore by Sea. You can read about her successes and failures on her blog Here Fran explains a little of the history of natural dyes and suggests projects for you to try at home.

How to make Natural Dyes with Onion Skins

When did you last wear anything dyed with flowers, leaves or roots? A couple of thousand years ago, only Roman emperors were entitled to wear a totally purple toga, in a specific colour which had to be dyed with a madly expensive extract from Mediterranean sea snails. In nineteenth century Britain, the roots of madder plants gave soldiers’ jackets that distinctive scarlet colour. These days, we are accustomed to a whole spectrum of clear, even, synthetic colours, but we’ve largely forgotten the richness and subtlety of natural dyes. Dye plants still grow all around us, the weeds sprouting from a ditch might be weld plants, which give a vivid acid yellow when fermented. The ordinary looking green leaves of woad can dye fabric blue, if you know how to prepare them.

For thousands of years, ways of using plants for dyeing were common knowledge. Now, the dyer’s work has become an unusual sight – trust me, you get some funny looks from passing drivers if you’re out on the side of the A48, collecting a load of dandelions for the pot. Why would anyone go to the trouble of making their own dyes? Well, look at this picture. It shows samples of wool, cotton and silk and every single colour among them came from onion skins. Though plant dyeing is a hugely complex subject, onion skin dyes are simple. There’s no need to start keeping stale urine to make your own natural woad vat, read a big book about mordants (fixatives) and modifiers or invest in lots of new equipment. All you need is onion skins and water. I hope I’ve made you curious enough to try the following project and find out for yours elf how interesting and beautiful plant dyes can be.

Brown Onion Skins

Onion skins hold natural dyes which are cheap to get hold of, easy to use and safe to experiment with. The general principles for simmering up a dye bath of plant material, include working in a well-ventilated area with pots and pans that won’t be used for cooking. This is because plants contain many compounds, some of which can be toxic. Onion skins are not poisonous, in fact, onion skin soup is supposed to be super healthy. It is fine to make onion dye in any kitchen saucepan, you can even use it to colour the shells of boiled eggs to eat for breakfast on Easter Sunday.

First, start saving the dry, papery, outer skins of onions and keep them in a paper bag. Store brown ones separate from red, because they contain different dyes. Either kind will work well on natural fibres, such as wool, cotton, linen or silk. If you would like to dye yarn for knitting, make sure it is made of pure wool rather than acrylic. Similarly, if you are looking for suitable items for this project in a charity shop, check the labels to see what they are made of. To find out how many onion skins you will need, weigh your chosen material. For the strongest colour, collect an equal weight of onion skins, half or quarter the weight is fine, less onion dye just gives lighter shades. A whole carrier bag of onion skins would probably only weigh 100g, so you might start by experimenting with 25g onion skins and a 50g ball of wool yarn.

Samples of Dye Baths

To make 50g of wool into two skeins of yarn ready for dyeing, get someone to hold one end of the ball, standing with their arms out, hands about shoulder width apart. Wrap the yarn in loops between the backs of their hands. Once you think you are halfway through the ball, you can weigh the remainder to see if you still have 25g left. Cut the yarn and tie the two ends together in a bow. Use cotton thread to tie loosely round the all the strands at four points on the loop – this will stop it getting tangled up when you slide the skein off the aching arms of your friend. Now make a second skein with the other half of the ball. You can make skeins on your own by wrapping the yarn round a straight backed chair.

Put the onion skins in a large pot with plenty of water and simmer them for an hour. Happily for the dyer, there is hardly any smell from cooking onion skins. Leave the pot to cool slowly overnight. Before you go to bed, put the stuff you plan to dye into a bowl of water, so that it will be thoroughly soaked by morning. Next day, sieve the onion skins out of the dyebath by pouring it into another pot through a colander or a piece of net curtain. The dyebath from brown onions should be deep yellow, a red onion dyebath looks red. Place one 25g skein of yarn or your other wet material into the dye. It needs to submerge completely to dye evenly, so try to release any trapped air pockets that are making fabric float to the surface.

If you are working with wool, it is safest to heat the dyebath slowly and keep it below boiling point, to avoid felting. Although many natural dyes lose colour if they are overheated, onion skin dye seems to absorb better, the longer and higher you heat it, so a full boil is not otherwise a problem. The most important thing is patience. After simmering for about an hour, leave your yarn or material in the pot to cool slowly. The deepest colours come from waiting until the next day to take it out, when you can rinse with several changes of luke warm water and let it dry. The water in the pot will probably still have some dye left in it. If you repeat the process with the second skein of wool or some other natural material, this will be dyed a paler shade than the first.

Brown Onion Dyes

Red Onion Dyes

The results of plant dyeing are never entirely predictable. Brown onion skins generally give yellows, golds and gingers. The depth of colour depends partly on the ratio of the weight of onion skin to the weight of material in the dye pot. The type of fibre the material is made of also has a big effect. Silk fibres typically take up dye quickly and gain rich colour more easily than wool, while cotton and linen take longer to absorb dye and generally have more muted colours. Unexpected things may occur. Red onion skins usually dye fibres brown, silk may take on brown with a reddish or a purple tone. I was surprised to find that pieces of cotton fabric cut from an old shirt came out of a red onion dyebath looking green, although wool and T shirt cotton in the same dye bath turned brown and a skein of cotton yarn in another red onion dye bath went dull purple. I am still not sure how that green happened.

Onion skin dyes are substantive, which means that they fix their colour onto fibres without any mordant. If you enjoy this project and start looking around for other plants to try dyeing with, you need to know that many plant dyes are adjective – they can’t fix on their own. If you simmered up a daffodil petal dye bath, most of the yellow colour would just stay in the water unless the wool or silk you put into it had been mordanted. There is plenty of information about mordants, dye plants and methods on the internet, though in my experience, a lot of trial and error is involved in discovering what will actually work for you.

Every natural dye bath is unique – have fun experimenting in this wonderful world of dying!

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