Isatis tinctoria („Färberwaid“ in German) but more commonly known as woad or pastel, has a long documented history as both a medicinal and dye plant. Woad is native to the steppe and desert zones of the Caucasus, from Central Asia to East Siberia and West Asia, but is now also found in Southeast and Central Europe and in western North America. The plant belongs to the family Brassicaceae (the mustard family), as do broccoli, cabbage and rape seed.
Woad is a biennial plant, meaning its life cycle is two years. It has a rosette with a thick, deep taproot in the first year. The leaves are harvested for dye production at this stage and only in the first year, as they have little or no color in the second year. During the first summer and autumn, one and the same plant can be harvested several times. In the second year, the plant produces around 1-1.5 m tall stems with small, yellow flowers, sets seeds, and dies. When woad produces seeds, it will readily self-sow wherever possible.
Generally, woad seeds are sown directly in early spring (March) in warmer climates and planted in seed trays in cooler climates. Woad seeds have a germ-inhibiting coating around them that needs water and constant moisture to break down. Pre-soaking the seeds in water will aid germination. Given the right conditions, germination usually occurs in about two weeks. When woad seedlings have formed their second set of true leaves, they can be transplanted if necessary.