Groundhogs can be a menace to your yard. They dig up your lawn, eat your plants and vegetables and make large networks of tunnels around your property. If you want to get rid of them but don't want the residual poison in your yard after they are gone, try glycerin. It will stick crushed jalapeno pepper to everything it comes in contact with and will stay there for a very long time, making the tunnels uninhabitable.
Boil the water and add the glycerin and jalapeno pepper. Cover and simmer, stirring regularly for 15 minutes or until the mixture has a soup-like consistency.
Fill in all the holes made by the groundhogs except one. Pour the solution down that hole.
Turn on your hose and place it in the hole with the solution. This will spread the solution throughout the groundhog tunnels. When water starts to leak out of the hole, remove the hose. Wait for the solution to stick to everything in the tunnels, the groundhogs included.
Do this in early spring, as the groundhogs will have just ended their fertilization period and will have newborn babies in their tunnels. This way, the babies will not be able to escape to make future generations.