Indigo (indigofera tinctoria) species are the world's only source of natural, true, colourfast blue. A magical dyestuff that has been used around the world as a dye since pre-historic times, the culture and wonder that surrounds this plant is immense.
Indigo cannot be dyed in the same way as other dyes, but must be used to create a "living" vat, which is achieved through a sort of fermentation process.
This kit contains the pre-measured ingredients to create one organic fructose vat, with which you can dye quite a bit of fibre - how much a kit will dye depends on a few things, including how dark you want the blue to be, and what fibres you use. But it will dye a lot! As a general ballpark, you could expect to dye at least 5 yards of a medium weight cotton such as a quilting cotton, to a medium blue, and probably more, and darker if you wish.
The vat can remain active for several weeks, depending on how much you use it.
Indigo can only be used to dye natural fibres, not synthetics.
The kit also includes comprehensive instructions on how to create the vat, how to use it for dyeing, and soda ash to use as a scouring agent for your fibres prior to dyeing.