12-16 oz coffee cup with 2" of apple cider vinager. (not the white vinager)
Add a small drop of dish soap to break surface tension...gnats drown.
Nematodes. I use Naturesgoodguys. $10 for a couple million. :)
they eat the larve in the soil.
Metal halides/HPS lights do a nice job of frying them lol!
Cheers!