Stinging Nettle

Mulch once a year in winter while the plants are dormant. Nettle wants soil with high organic content, around 4 to 5 percent, and a pH anywhere from 5.0 to 8.0, so an annual organic mulch is most of the feeding this crop needs. The mulch feeds the soil as it breaks down and holds moisture, which matters because nettle is a moist-ground plant that does poorly once soil dries out.

In spring, scatter seed in a dense layer on the surface of moist soil and press it lightly in, or cover with only a very thin layer of soil. Expect germination in about 14 days, then thin the seedlings. To get a head start instead, seed flats in a greenhouse in late winter and set the transplants out in early spring, eight inches apart. Nettle seed is tiny and needs light and constant surface moisture to germinate, so burying it deeply is the usual reason a sowing fails.

Through the growing season, keep harvesting the tops just above a node rather than letting stems run up. Repeated cutting drives new leafy shoots and delays bloom, extending the window of tender pickable growth. Removing the growing tip prevents the plant from setting flowers and pushes it back into vegetative growth, which is the part you actually eat.

Gather in early spring while the growth is tender, ideally early in the morning and before the plant flowers. Take leaves no wider than three inches from plants under three feet tall, clipping with sharp scissors right above a node at an angle so the cut stem does not sit waterlogged. Collect into a paper bag or basket, and take only what you need rather than digging plants up. Once flowers appear the greens turn tough and lose flavor, so the eating window is the flush of soft growth that comes before bloom.

Water to keep the soil moist during the harvest season rather than letting the bed swing dry between cuts. Nettle is at home on moist forest floors, streambanks and riparian edges, and it will take occasional wet feet. Nettle does not perform well in drought; dry soil checks the tender regrowth that repeat cutting depends on.

Dig rhizomes in late fall once the top growth has died back. Rehydrate them, divide if you want more plants, pot up or plant out eight inches apart, cover lightly with soil, and water in. If any leafy growth is still attached, prune most of it off before replanting. A perennial like nettle establishes best while dormant, and cutting back the foliage stops the transplant from losing more water through its leaves than the disturbed roots can replace.

Cut the flowering seed heads in fall to keep the patch from spreading. Close mowing of a stand does the same job by preventing fruit from developing. Seeds mature in late August or early September and the dry fruits hang on the plant until frost, so there is a real window to catch them. A nettle shoot in full sun can set 10,000 to 20,000 seeds, and the seed stays viable in storage for years, so letting one season shed is how a patch becomes a colony.