I haven't done this since I was seven
I went on a dyeing workshop yesterday, which was lovely. We were dying unspun sheep wool with garden plants. We also had an indigo dye bath which was very interesting because when the material is taken out of the dye it is green and it only turns indigo blue as it oxydises. I did tie and dye using an old sheet (that had been previously sides-to-middled and then worn out again and sent to the jimble jumble sale where I found it), which I last did at primary school. Good fun.