Cotton fibres are lucky if they're an inch long, but they're the seed ball fibres.
Linen fibres are actually only as long as the stem, the fibres we use are the water carrying ones, and with nettle they're only really about four inches long when properly retted out.
Mostly we use the long lengths that are still bound together with some of the rest of the plant cell walls keeping it all together.
Properly made nettle fibres, or hemp, ramie, are fine, as fine as linen, and they come out white whereas linen comes out pale fawn and hemp is a darker shade.
They bleach, sun brighten to white, but the nettle is whiter to start with.
I have spun and woven nettle cloth, it is lovely stuff, but it's a lot of work. I think if I had enough area to grow a decent crop, to make it worthwhile retting out a lot of them (and mind it stinks as it rots, it really, really does, and you can't flush that stuff into any watercourse without upsetting things because it's anaerobic. That's the reason that the lindens were pits where flax was retted.
You can 'dew rett' all of them, but with nettle you have to be incredibly watchful because it'll go to mildew very quickly.
In drier climates than the west of Scotland, they used to let the nettles stand over Winter, and before Spring really came in and the agricultural year took off hard again, they pulled the stems and beat the fibres free from them. Netherlands, Germany, Latvia, etc.,....slightly different climate to our sodden wet one.
