While the adaptability and perseverance of our common snakes makes them extremely difficult to eliminate entirely, removing potential shelter can significantly reduce the number of snakes in an area. Shelter for snakes is almost anything close to the ground that they can enter or get beneath to avoid predators and extreme temperatures. Boards on the ground, log and leaf piles, cracks and crevices in foundations, rock walls, ground-hugging shrubbery, dense patches of vegetation and narrow spaces beneath decks and outbuildings are all popular forms of cover. The number of snakes around a home can be reduced by sealing or removing some or all of these shelters, but use common sense. A nearly snake-free yard would have a wide, close-cut lawn extending right to a tightly sealed foundation: No flower gardens, no rocks, no shrubbery. Unless you really want to surround yourself with a boring, uninviting landscape, it is much easier to live with an occasional snake in the yard.A snake in the house is another matter. While milk snakes may live undiscovered in rock foundations for generations and the pretty little "ringnecks" may survive comfortably amid the debris of a dirt-floored crawl-space, most snakes - especially garter snakes - end up in houses by accident. They cannot live in such habitats for long. Most are victims of falls and a poor sense of direction. They usually turn up in the spring, having hibernated in the foundation and emerged on the wrong side of the wall.A snake in the house - especially in the typically jumbled cellar - is not an easy animal to locate. If it's any consolation, the snake will probably avoid living areas. If you can find it, check to be certain that it is a harmless snake, grab it with a pair of work gloves, and let it go outside. If the snake does not present itself, it may be lured out by the warmth of a heating pad or a sunlamp shining on a damp towel (but beware of the fire hazard!) It can also be trapped by placing "glue boards" (normally used for rodent control and available at hardware and agricultural stores) against walls in an area that the snake is likely to cross. Glue boards should be checked daily; captured snakes can be released unharmed with a little help and an application of common cooking oil.There are no safe, effective snake repellents capable of keeping snakes away from yards or pools. However, if snakes are inhabiting small, confined areas - such as that crevice behind the front steps - a few tablespoons of naphthalene ("moth balls") may temporarily drive them out so that the entrance can be sealed.
An even better question would be, why would you WANT to get rid of Garter Snakes?(There's no such thing as a "Gardner" snake) They are harmless and generally docile, and they don't cause any damage to lawns, flowers, gardens or people or pets. There are no snake repellents that actually work, that won't kill or hurt children or pets. Natural snake predators, like King Snakes, can be a deterrent, but again, that's a snake, also. If snakes are hanging around a property, it's because something on the property is attracting them and keeping them there. Getting rid of whatever is causing them to hang around is the best option. Garter Snakes eat frogs, toads, and fish, primarily, so if you've got permanent water on the place that allows those animals to breed, then you will have things that show up to eat those animals. Draining wetlands or permanent water sources can get you in MAJOR legal problems with the Federal government, so you really do not want to go there. Snakes are also attracted to things that provide shelter and hiding places, like woodpiles, trash piles, stacks of old lumber or sheets of metal on the ground, dense bushes and shrubbery, tall grass...so keeping those things under control will minimize their attractiveness to wildlife-MINIMIZE, not eliminate.
What I do is throw moth balls under the house and a few in the closets, one under the bed, and under the sinks. This helped me. The house smells like moth balls, But better the having snakes in the house.
Pick them up then put them in the woods