Garter snakes, commonly known as "garden snakes," are found all over the North and Central America continents. These many species of the genus Thamnophis are non-poisonous and pose no threat to humans. In fact, their feeding habits make them extremely helpful in suppressing vermin populations near human habitations. Nevertheless, many people find these small reptiles alarming and would prefer not to encounter them.
Remove Snake Habitat
Snakes like to hide and hunt in cool, damp places. Minimize the amount of area in your garden or yard that meets this description. Keep the lawn mowed short to deny them hiding spots in tall grass. Move wood piles away from the area to be kept clear of snakes. Keep compost heaps and brush piles at a distance. And don't plant shrubs or bushes in any area you want snakes to stay away from.
Remove Snake Food
Snakes primarily eat small rodents and large insects, chief among them mice, rats, grasshoppers and crickets. To keep from attracting snakes, take steps to prevent attracting what they eat. Keep a tight lid on grains and pet food. Clean up all food debris promptly.
Build a Snakeproof Fence
The Colorado State University Extension describes making a snakeproof fence to keep snakes away from areas where children play: "Use 36-inch high galvanized hardware cloth with a 1/4-inch mesh and bury it 6 inches deep, slanted outward at a 30-degree angle. Make certain the gate fits tightly and swings into the play area." Snakes cannot climb this fence if it's constructed correctly. Plants can, though. To prevent a snake-friendly ladder growing next to your fence, keep it clear of vegetation.
Use Snake Repellent
Buy a commercial snake repellent and apply it wherever you want to keep garden snakes away. Jonathan Hatch, author for the website How To Get Rid Of Things, recommends two brands: Liquid Fence and Biodefend. Among other substances popularized as snake repellent but whose efficacy is not supported by experimental study are gourd vines, moth balls, cedar oil, lime, cayenne pepper spray, sisal rope, coal tar and creosote, liquid smoke, artificial skunk scent and king snake musk.