Natural dyeing and mordanting cotton fabric + avocado dye

It has been a while since I have written here! I have been using this blog a lot though as an notebook I go back to when I need to fresh my memory on some natural dyeing I have done. Just because I have not written here doesn’t mean I have not done any natural dyeing life just has been really busy. I have been active on my Instagram though @_theeasyblues_. Lately I have done more cellulose fabric dyeing and eco printing and I’m experimenting with some new things at the moment. I though it would be good to write them down here, so I can come back to them when I need to, and if someone else finds them useful even better.

I think mordanting fabrics and yarn before dyeing is important, so that the fiber will take the dye in better and that the colours will be brighter and last longer. Some colours are okay without mordanting but some really need that extra boost. I have done a post about how I mordant wool yarn with alum before, I will put a link here. I do the almost the same mordanting with alum to cotton, but because cotton is an cellulose fiber it will need some tannin to work better. There are many ways of mordanting cellulose fiber, what I use is tara powder which made from the seeds of a tara plant native to Peru and it has lots of tannin in it. I think some people use soymilk and iron also has natural tannin in it as well.

The following instructions to using tara powder are from Finnish Riihivilla online shop website where I buy my tara powder from.

200g of tara powder is enough to mordant 1kg of cellulose fiber fabric (cotton, hemp, linen) together with alum. I first mordant with tara powder and then with alum. Tara powder will give a small hint of beige to the fabric, but I have never found that to be a problem.

I dissolve the tara powder into 60°C water. I pre soak the fabric in water before adding them into the pot. Make sure there is enough water for the fabric to move around. I let the temperature rise to 90°C and then keep it there for an hour and let the fabric lie in the water until its cooled down, usually until the next day. I rinse the fabric carefully. After this I mordant with alum. Keep in mind that you need douple the amount of alum to cellulose fiber than wool (20g/100g of material). Its good to remember to weight the fabric dry before you soak it in water, I have done that mistake couple of times in the past. You can use the tara powder liquid for the second time and this time add only half of the amount of powder you used before.

And then on to dyeing! Dyeing cotton really doesn’t differ from dyeing wool much so all of the posts that I have done about dyeing wool yarn with different things will work fine. Lately I have been loving dyeing with avocado skins. I have used this very usefull post from Rebecca Desnos.  This post has really good tips on how to get really good pinks from avocado skins. She uses soy mordanting. I really need to read her book to learn more about that!


I have been very specific about cleaning the skins from the flesh really good to get bright colours. I also made the mistake of storing my avocado skins in a glass jar (they go moldy) so now I store them in a cardboard box. I also checked the ph levels in our tap water and made it more neutral with some baking soda. I have gotten nice pinks, but like always with natural dyeing you can never know exactly what you will get. Above I have two different pinks from two different times. I’m also writing about eco printing at the moment. Lets see if I can keep up this documenting thing!