i do this every year and it works absolutely great (10% dilution). using just nettles and comfrey will give an npk balanced fertilizer. i also like to add chopped spring shoots of willow, because there is rooting hormone in them.

this year however i have a duck pond, so i will start using that too. i toss seaweed, algae and duckweed in the pond for the ducks to eat (and poop). i will just pump the pond water on the garden beds and top up the pond from the well, keeping the pond from turning smelly.

i just hope the pond water wont be too strong, must do some trials.