Gather nettles. A lot. This recipe yielded one quart, and I had about 4 -6 cups of chopped nettle leaves.
Chop your nettles coarsely, and put into a large bowl with 1 tbsp salt. Chop 1/2 cabbage head finely. Add to the bowl of chopped nettles with another tbsp of salt. Slice 1/2 red onion finely. Add to the bowl.
Massage the nettles and cabbage and salt with your hands for 5-10 minutes, until they begin to release their juices. If you are concerned about getting stung, you can beat the cabbage & nettles with a mallet, clean jar or other tool, but I used my hands, and didn't have any problems with getting stung.
Stuff into a jar, and press firmly until the juices flow over the top of the kraut. Top with a grape leaf to keep it crunchy. Cap firmly- after ensuring the liquid completely covers the kraut (if not, add brine (salt water) to cover.) Set aside on a dish to catch any overflow, for a week, minimum. Longer makes a more sauer kraut