The Humane Society states that fencing, scare devices, removing high grass and debris and closing burrows deter groundhogs from invading gardens. Groundhogs may leave the property if burrows are disturbed.
Both standard wire fencing and electrical fencing can be used to keep groundhogs out of the garden. The Humane Society recommends placing one strand of electric fencing around the perimeter of the garden 4 inches off the ground. Chicken wire or another tightly woven fence can be placed around vegetable gardens to keep groundhogs out. The Humane Society recommends fencing that is at least 18 inches high and unsecured at the top to prevent the groundhogs from climbing into the garden.
It is possible to force the groundhogs to relocate by disturbing burrows. Horticulture.com recommends placing a small amount of used cat litter in burrows to encourage the animals inside to move elsewhere. Commercial deterrents are also an option. Place commercial deterrents around the perimeter of the garden and near groundhog burrows. Remove debris, such as tall grass and tree limbs, to locate burrows and eliminate groundhog shelters on the property.
Scare devices can also be placed near gardens. Balloons or beach balls should be tied in an area where the wind will cause the objects to move. The Humane Society explains that the movement should frighten groundhogs and keep them out of the garden.