Stinging nettle is a fast-growing plant; young plants reach maturity by mid-season when planted in the spring. This plant is mildly toxic to humans and of variable toxicity to pets. If you’re working with a stinging nettle plant in your garden, always wear protective clothing. This includes thick gardening gloves, as well as long sleeves and pants. Avoid touching your face as you work.
Light
Stinging nettle thrives in full sun conditions but will tolerate some shade. Too much shade makes the plant grow too tall and leggy. Stinging nettle is especially fond of rich, moist soil, so gardens can become overrun with this plant unless you are careful. You can keep in check by removing the flowers as they appear to prevent self-seeding. Regular harvesting will also keep the plants under control. At the end of the season, the leaves and stems of stinging nettle make a good nitrogen-rich addition to the compost heap, but it’s best to avoid adding the flowers and seed heads to compost. MarioGuti / Getty Images kulbabka / Getty Images
Soil
This plant does best in evenly moist, loamy soils rich in nitrogen and phosphorus. It often thrives in disturbed soil, which is why it is often found growing in abandoned lots and building sites, provided the underlying soil is rich. It tolerates a wide range of pH levels, from very acidic to very alkaline. It does not do well in very dry, barren soils.
Water
Stinging nettle has average water needs but will be especially vigorous in climates with frequent rainfall. Mature plants have a good tolerance for short periods of drought, but this is not a plant that does well in arid climates. If your region has regular rainfall (every two weeks or so), additional watering is not necessary.
Temperature and Humidity
Stinging nettle does well in all climate conditions across its hardiness range, USDA zones 4 to 10. It is more at home in humid climates but will grow adequately in dry atmospheric conditions, provided it has adequate soil moisture.
Fertilizer
Nettles thrive on nitrogen-rich soil, so periodic feeding with compost or a nitrogen-heavy fertilizer will help plants that are growing in poor, barren soil. But in most typical garden soil, stinging nettle does quite well with no feeding at all.
Types of Stinging Nettle
Here are six common subspecies of stinging nettle, but only five have stinging barbs:
Urtica dioica subsp. afghanica: This plant is native to central and southwestern Asia, and it sometimes does not have stinging barbs. U. dioica subsp. dioica: This nettle is commonly found in Europe.U. dioica subsp. gansuensis: This plant is found in China.U. dioica subsp. gracilis: Known as American stinging nettle, this plant is found in North America.U. dioica subsp. holosericea: Known as hoary nettle or mountain nettle, this plant is found throughout western North America.
Pruning
Deadheading spent flowers will stop stinging nettle from spreading uncontrollably through self-seeding. Other than this, no pruning is necessary, other than pre-winter removal of dead stalks.
Propagating Stinging Nettle
This plant is easy to propagate simply by digging up plants from an existing patch and moving them to a new location. Here’s how:
How to Grow Stinging Nettle From Seed
Stinging nettle is easy to grow from seeds collected from existing plants. This is most often done with seeds collected from mature seed pods, stored for the winter, then sown indoors in seed trays six weeks or so before the last frost. The seeds are very tiny. Scatter them over the surface of a tray filled with ordinary potting mix. Press them lightly into the mix, and barely cover them with a bare sprinkling of soil—they need some light to germinate. Keep the tray lightly moist until the seeds sprout, which happens within about 14 days. The seedlings can be transplanted outdoors as soon as the soil is warm enough to be worked.
Overwintering
No overwinter protection is needed for this hardy plant. Most gardeners will want to cut back dead stalks in late fall to prevent self-seeding in the garden.
How to Get Stinging Nettle to Bloom
Generally speaking, you don’t want this plant to flower, as it leads to unwanted spreading through self-seeding. The flowers are not showy, and there’s no aesthetic reason to encourage blooming. The exception is where you want to observe the butterflies and other pollinators that are drawn to stinging nettle, or if you are intent on collecting seeds for propagation. If you do want to experience flowers, make sure the plant is getting enough water and sunlight—flowering is almost guaranteed. Harvesting involves cutting back the top third of the plant, just above a node where leaves branch out. This will encourage new growth. The leaves will have the best flavor in cooking if they are harvested before the plant flowers. After this, the leaves because somewhat tough and stringy. The leaves of stinging nettle can be used in the same way—and in the same recipes—as you would use cooked spinach. It’s helpful to have a tarp nearby that you can put your plant clippings on, so they don’t get lost in your soil or grass. Either compost them or seal them in a yard waste bag. Furthermore, to make sure new shoots don’t spring up, you can cover the site with a tarp or piece of cardboard for at least one full growing season. This will smother any new plants that try to grow. North American gardeners will find that burning nettle has some appeal to native butterflies, though it does not serve an ecologically critical role for them.
