Woad is still used for the indigo dye, which is extracted from the leaves of the plant. It’s uses lie mainly in the textiles and cosmetics industries. The UK market is estimated to be 40 million tonnes/year, which would require about 1,000-2,000 ha to supply this.
Seed was traditionally sown in spring, February to March, preferring well-drained, loamy soils with a pH 7. Leaves are harvested up to three times a year, the first occurring as the plant comes into flower with following cuts up to October. Yields are very variable with an average of 20t/ha, but this could reach 40t/ha, giving 1-2 kg indigo/t.
Woad is a fairly ‘hungry’ crop therefore it is suggested that it should be fertilised similar to winter oilseed rape, applying 50-150 kgN/ha.