1. Water
Woad needs water and lots of it to germinate, grow, and thrive. Usually, you would plant woad in the early spring and immediately water the soil to saturation. For one thing, the seeds will not germinate unless there’s plenty of water. Otherwise, the natural inhibitor in the seeds will keep them from sprouting. You need to keep the soil wet during the first few weeks of the plant’s life until the taproots establish themselves. Once the plant is fully grown, then you don’t have to worry about watering it that often even during the summer months. The deep roots usually get their own water needs from the soil.
2. Light
As a native of the Mediterranean, woad is accustomed to the bright sun of Southern Europe. Woad needs full sun as much as it needs water to produce a good indigo crop. Since you grow it in the early spring, that exposes the plant to frost. Beware of the cover you provide your plants to protect against frost. The same cover might cut off the plant’s exposure to the sun and reduce the indigo crop. Ironically, even frost damage doesn’t impact the indigo yield as much as sun deprivation. So keep that in mind the next time you decide to cover your woad with a tarp.
3. Mulch
It’s not often that you find a plant willing to forego fertilizer for the sake of mulch. However, you’ll still need to fertilize your woad a lot to ensure the indigo and seeds are plentiful. The benefits of mulch are abundant from water retention to soil aeration, both of which are needed to grow woad. Mulch also inhibits the growth of weed and pests. So before you plant your woad, add a liberal layer of mulch, about 6 inches, between the rows of woad. Later you’ll need to replenish that as the plants start to flower.