Our natural dyes can be used to dye any natural fibres. You can use garments, fabric, yarn, unspun fleece, housewares such as napkins or tea towels and more.
It should be 100% natural fibre, but can be cotton, linen, hemp, silk, wool, alpaca, mohair, etc. If your fibre has a very small amount of synthetic fibre, such as a t-shirt that is 95% cotton 5% elastine, or a sock yarn that is 95% wool, 5% nylon, it will still dye without much noticeable difference.
However, if it has a higher synthetic content, such as a 50/50 cotton/polyester blend, it will greatly affect the colour. Only the cotton, or natural fibres, will dye, and the synthetic won't.
In general, this will result in significantly paler shades.