A couple of articles in the latest issue of Väv (a Swedish weaving magazine) talked about nettles and their uses as spinning fiber. Traditionally they’re harvested from August (some say midsummer), but one mentioned “before flowering” which they are doing now.
And since you can’t learn anything new without experimenting, I’m going to collect a batch now, in one month and in August. The longer you leave them, the coarser the fiber – in fact you can just leave them to wither and harvest in late winter = auto-retting. Retting is the process of rotting the woody bits of the stalk so that you can separate them from the softer fibers.
So the stalks are left to dry for a year, then retted, then broken, cleaned and carded for spinning. To get them really soft, the lady who harvested early boiled her fibers too. A bit of a long term experiment with nothing much happening, and then if it’s a succes you’ll curse yourself for not preparing a ton of them I suppose.
One source mentioned getting 200 g of yarn from 1 kg of stalks. But I don’t know if that’s the fresh or the dried variety. Suspect the latter.
I’ve ordered a couple of 100 yo articles from the library, that might be interesting.