How to Grow and Use Stinging Nettles

The best free feed in the garden, from a plant most people are trying to kill.

Most people meet nettles by accident, usually with a bare ankle. If you already have a patch you are ahead, because nettle is one of the most useful weeds in a New Zealand garden: a free liquid feed, a compost activator, and a green you can eat.

Nettle grows throughout New Zealand given moisture and a bit of shade, from Northland to Southland. Do not confuse it with ongaonga, the native tree nettle, which is far larger and genuinely dangerous.

Read this before you plant any

Nettle spreads by creeping underground stems as well as by seed, and it can form a solid colony that covers a great deal of ground. It is treated as a weed in most places and is a declared weed in some. None of that makes it a bad plant, but it does mean you plant it on purpose, in a place you have chosen, or not at all.

• Check your local rules first. Weed declarations are set locally, so look up your own council, county or regional authority before deliberately establishing a patch.
• Contain it. A large pot, a tub with the base cut out and sunk into the ground, or a bed bounded by mown grass on all sides. Mowing is the simplest barrier there is.
• Cut before it seeds. This is the single habit that keeps a patch a patch.
• Do not put it somewhere children run. The sting is harmless but genuinely painful, and it lasts minutes.

Where to put a patch

Nettle wants what most gardeners have too much of: a damp, rich, part-shaded corner. Behind the shed, along a fence line, at the drip line of a tree, beside the compost bays. It thrives on disturbed ground with plenty of nitrogen, which is precisely why it turns up around old animal yards and compost heaps on its own.

Poor dry soil in full sun will keep it small and sulky, which is one way to hold a patch in check if you want one anyway.

Growing it

The easiest start is a division. Lift a clump of an existing patch in the cool season, take a piece of root with a shoot on it, and plant it where you want it. Wear gauntlets. Seed works too and is sown on the surface in spring, but division is faster and you almost certainly have a donor patch within walking distance.

After that it needs nothing. No feeding, no staking, and watering only in a long dry spell if you want to keep cutting it.

Harvesting without getting stung

Cut the top third of each stem with shears, into a bucket, wearing gloves and long sleeves. Take the young growth: the top four to six leaves are tender and mild, and older leaves further down get coarse and gritty.

Cut a patch two or three times a season and it will keep producing soft new growth. Cut it hard before it flowers and you get better leaves and no seed set, which solves two problems at once.

Nettle feed, the reason most people keep a patch

Nettle is high in nitrogen, and useful amounts of iron and magnesium. Steeped in water it makes a free liquid feed for leafy crops, and it is at its best in spring when everything is growing hard and wants nitrogen.

1. Fill a bucket or bin loosely with cut nettle, stems and all.
2. Cover with water and put a lid on it. The lid matters more than you think.
3. Leave it two to three weeks. It will smell genuinely foul. That is the process working, not a fault.
4. Strain off the dark concentrate and dilute it about one part to ten parts water before it goes anywhere near a plant.
5. Water it onto the soil around leafy crops every couple of weeks in the growing season. Keep it off the leaves.

Go easy on anything you want to flower or fruit. A nitrogen feed on tomatoes or capsicums in flower gives you a magnificent bush and very little crop. Save it for lettuce, silverbeet, brassicas and anything else grown for leaf.

The spent leaves go in the compost, where they work as an activator in their own right. A layer of fresh nettle through a heap that has stalled will often restart it.

Eating nettles

Cooking or thorough drying destroys the sting completely. There is no trick to it beyond that, and blanched nettle tastes like a deeper, more mineral spinach.

• Pick only young spring growth, the top few leaves, before the plant flowers. Older leaves develop gritty crystals that are hard on the kidneys.
• Blanch for a minute in boiling water, then use as you would spinach: soup, pasta, pie filling, or squeezed dry and folded through a risotto.
• Dry it for tea, or freeze it blanched in balls for the winter.
• Wash and handle with tongs until it hits the water.

Do not eat nettle from a roadside, a stock yard or anywhere that may have been sprayed. Nettle takes up what is in the soil, which is the same reason it makes good feed.

Feeding the wildlife too

A nettle patch is a nursery. Several butterflies lay only on nettle, so the caterpillars you find on it are the reason you get the butterflies elsewhere in the garden. Leave one corner uncut through the warm months if you want that, and cut the rest.

If you change your mind

Nettle is persistent but not invincible. Cut it to the ground repeatedly through a full growing season and it exhausts itself, because every regrowth spends root reserves. Digging works if you get the rhizomes out, and any piece left behind will start again. Smothering under heavy cardboard and mulch for a full season works with the least effort. Whatever you do, do it before it seeds.

See also: Make your own feeds and sprays and Comfrey in the Plant Library, the other half of a free feed bay.