The secret to successful natural dyeing of cellulose fibres, yarns and fabrics such as cotton and linen is thorough scouring. The scouring process removes natural oils, waxes and pectins from the fibre so that the dyes can penetrate the fibre more readily. Scouring and mordanting cellulose fibres is a more time consuming process than when mordanting wool and protein fibres. But it is well worth taking the extra time to prepare your fabric before you put it into the dyepot.
Phaeolus schweinitzii fungi produces Yellow, gold natural dyed yarns
A selection of Natural Dyes and Mordants
A simple how to recipe for making an alum mordant, used for natural dyeing
Learning to use natural dyes
Dye recipes, and projects for the natural and organic dyer