The latest tutorial on planting techniques and methods for Isatis indigotica (woad)

Isatis indigotica has no great requirements for soil in its growth habits; basically it can be successfully planted in ordinary soil. It is tolerant of severe cold and prefers warmth, but fears waterlogging, and can grow normally in the Yangtze River basin and the vast northern regions of China.

Isatis indigotica is propagated by seed, with spring sowing and summer sowing. Spring sowing: between March and May, choose well-drained, loose and fertile soil, and draw furrows 15 cm deep at a row spacing of 18-20 cm. Evenly scatter the seeds into the furrows, cover with soil, tread once with the foot, or push twice continuously with a large hoe, then rake level and water. Generally at around 18°C, seedlings emerge in 7-10 days. Summer sowing: between June and July, the method is the same as spring sowing, with seedlings emerging in 4-5 days.

Field management: when seedlings are about 6 cm tall, thin them to a plant spacing of about 5 cm. From Xiaoman to Mangzhong, apply 15 kg of ammonium nitrate and 15 kg of superphosphate per mu as topdressing, then water after covering with soil. From Xiazhi to Xiaoshu, cut the leaves; 4-5 days after cutting the leaves, when watering, apply 10 kg of urea as topdressing.

Harvesting and processing: spring-sown Isatis indigotica is cut for leaves once during the dog days; cut the leaves from the base, and it is best to dry them for one or two days. From Hanlu to Shuangjiang, dig up the roots, dry them in the sun, and use them as medicine. For summer-sown plants, cut the leaves and dry them in the sun when digging up the roots, and the root-digging season is the same as above.