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!

Natural Dyeing: Mordanting

Before I started experimenting with plant dyeing I needed to mordant the yarns I was going to use. I collected all the white and grey coloured wool yarns I could find from my own closets and from the storage room of my childhood home. Some of the yarns where really old. I think that some of the curly ones are from my late aunt’s collections. The yarn might be from a pullover that was unraveled, so it could be made in to new things (everything needed to be saved).

Most of the yarn I used was 100 % wool yarn which is perfect for natural dyeing. Wool and silk absorb natural colour the best. In my experience cotton and linen and more difficult to dye, protein fibers work the best. Do you have any experiences with different materials? I noticed that there is a huge difference in how different kinds of yarns react to natural dyes.



But back to mordanting. Why is it important to do mordanting? This step is to ensure that the colour will stick to the yarn better and that it will be stronger. I wanted to pre mordant the yarn, because I have heard that the results are better that way. It’s also possible to mordant the yarn at the same time as dyeing it. But I think it is handy to get this step out of the way so I can concentrate into more fun parts of natural dyeing. First I winded the yarn into skeins and tried my best to keep them from tangling too much.


I used this very large pot that we use to boil water at our summer cottage (I’m struggling to find an English word for it). The amount of alum is always around 10% of the weight of the dry yarn. I had 1 kg of yarn so I added 100 g of alum.  I let it dissolve into small amount of lukewarm water and then mixed it with the rest of the water. I made a mintage here with the amount of water, it should be 5 litres of water towards 100 g of yarn. I didn’t use enough water but it seemed to work anyway. I soaked the yarn in water beforehand so it was wet when I added it into the pot. I brought the water to a boil and after that kept the temperature at around 80 °C. Wool yarn does not like to be boiled and boiling can also evaporate the alum into the air when the alum should be absorbed into the yarn. I just checked that the water was not bubbling and let the yarn stay in the pot for one hour.  It’s important to stir the yarn every now and then to ensure an even distribution of alum.






Lankojen puretus

The weather was as grey as the yarn I was working with and it also started raining, but I got the deed done. I dried the yarn for later use, but I always soak the yarn in water to make sure it’s evenly wet before adding it to the colour liquid, that way the dyeing result is going to be even.

There are other things one can use for mordanting than alum, but I like alum because it doesn’t change the colour of the yarn the way iron or copper do. Unless that’s what you want to do. Copper changes the colour into more greenish and iron brownish colour.  Later I discovered that many people also use cream of tartar together with alum. Cream of tartar should help the alum dissolve better into the water and to absorb better into the yarn. Live and learn! Next time I’ll do things differently but even so I think my way worked fine as well. Have you got any mordanting experiences? What has worked for you?

Ps. Make sure that the pots and other tools you use for mordanting and dyeing are only for dyeing not for cooking.