I have here five skeins of cotton (organic 10/2 from organiccottonplus.com) and I intend to make it yellow.

For a pleasant and successful experience dyeing cotton, you have to start by cleaning off the sizing that is added when the cotton yarn is produced. I do not know what chemical is used for sizing my cotton, but it cooks off really brown and smells rather sweet. I boil the cotton for about two hours in a gallon of water plus a couple of tablespoons each of washing soda and scent-free, plant-based dish soap. Then I rinse it sort of well and boil it again for another two hours or so, and then I rinse it better.

my pot weight 2333g, so I have 85g of plant matter. That is a ton compared to my 173g of yarn, but I am happy getting rid of this weed, and I will also be happy getting some very deep color.

After a couple of hours simmering and then an overnight soak, the dye is ready for straining. I compost the cooked greens.

I am ashamed that I did not take a photo of the yarn being mordanted; I steeped it in a solution of 20g (or so) aluminum acetate (wear a mask when you use it) for a couple of hours and then added about 20g of calcium carbonate, and then let it sit overnight. The mordanted yarn goes straight into the dye pot. Yellow commences.

That is a nice yellow, indeed. It will not be quite so vibrant once the yarn is rinsed and dried, but I am liking this a lot.

This actually has a bigger color pop than I was expecting to get from this plant.

Compared to my white yarn and my mustard cup, this is quite strong.

I used this purple yarn to tie my skeins, and it turned pink during the scouring process. All information is useful.

Cotton tends to really scrunch up during the dyeing process, so the skeins can pose a bit of a challenge when it comes time to wind them. I make balls first and then wind them onto my lovely cake roller.

I like to stretch these guys out a bit before I put them on the swift. They unroll without quite so many snags. But beware of snapping the cotton with an overly enthusiastic stretch. I speak from sad experience.

I followed the same procedure with this batch, but will add an iron mordant and let it sit for 5-10 minutes. I usually start by adding about a teaspoon of mordant, stir it in, see what happens, and then add more if I think the yarn wants it. I used to mix the iron with boiling water in a separate container, but sloth has prevailed and I just stir it into the pot, as far away from the yarn as possible.

I took this photo just seconds after adding the mordant.

It is nice to have company.