I choose cotton string for this project because it's 100% natural and cam be dyed in any colour, as well as easy to wash, either by hand or in the washing machine. If you want to you can easily dye to any colour, and if it gets wet it will dry quickly. I'm thinking that my first rug will go into the bathroom. But then again, I also need one for the bedroom. Guess I will have to make more than one.
To make the 25mm diameter crochet hook I used a regular 25mm pine dowel.