I found two pre-owned white cashmere sweaters in a vintage clothing store and dyed them with the same blackberry leaf dye bath but achieved very different results. I premordanted one sweater with alum before putting it in the blackberry leaf dye bath, and it became bright yellow. After dyeing the other sweater, I processed it with an iron aftermordant, which turned it teal gray-green.

You can have fun with this kind of experiment. Choose an old white sweater from your drawer or pick up one from the local thrift store. Check the sweater label: any sweater you use for this dye project should be 100 percent wool or another natural fiber to assure even dyeing.

Excerpted from The Handbook of Natural Plant Dyes: Personalize Your Craft with Organic Colors from Acorsn, Blackberries, Coffee, and Other Everyday Ingredients by Sasha Duerr, published by Timber Press. Images by Sasha Duerr.