A quick post for those of you interested in growing a plant to produce blue dye!
A member of the mustard family, woad has been used since ancient times to produce a beautiful blue dye. It is an easy to grow hardy biennial, but is classified as an invasive weed in some of the Western, dryer parts of the United States (check your local guidelines before planting). The blue dye is present in the first year leaves – only let grow into the second year if you wish to collect seeds.
How to grow:
Site Selection: Zone 4-8, rich loamy alkaline soil. Full sun is preferred. Rotate planting areas yearly and fertilize with nitrogen.
Start seeds: Start indoors several weeks before last frost and plant out after all threat of frost has passed, or direct seed into garden at about the time of the last frost about ¼” deep, 4” apart. Thin to 1’ between plants. Click here to buy organic woad seeds.
Harvest: Harvest the leaves from midsummer to before the first frost. Plants will re-grow leaves to allow a second or even third harvest. Only first year leaves produce blue pigment.
Processing: Rinse the leaves and use immediately in a vat for dye extraction.
Others dye plants: