My friend covers all the holes in his yard but one, then he empties a can of ether into the only open hole. He lights it, takes several quick steps backwards.............BOOOOOOM!!!!!!! His whole property jumps, dirt flies everywhere, flames eject from the holes, he checks for shrapnal and blood. Then he waters his lawn and garden and floods the holes.
You can consider this non-lethal if the varmants have vacated before detination.
Seriously though, you can always feed them. Give them plenty of goodies to deter them away from your garden.