Like rabbits, groundhogs and gophers are tricky animals to rid from gardens. Both types of animals use their burrowing abilities to reach vegetables at growing sites; but there is one distinct difference between the two animals: rabbits will burrow but not dig tunnels.
Rabbits can be stopped by trenching a metal fence into the ground about 6 inches; but what does a gardener do to rid groundhogs? After all, they will only burrow and drill more tunnels.
Groundhogs can be stopped by trenching a metal fence with PVC more than 6 inches. Some rodent experts suggest that trenching a metal fence at least 12-24" inches is best. This tactic will not completely rid groundhogs from landscapes; but it will reduce the amount of groundhogs seen on lawns and gardens.