Garter snakes are generally helpful creatures, consuming insects around your yard, yet their presence isn't always welcome. The snakes may find their way into your siding while looking for food or shelter among shrubs, rocks and other landscaping around your home.
Garter snakes aren't considered dangerous, but their saliva may irritate or cause a skin rash in humans, and the snakes can emit an offensive fluid from their anal glands, according to the University of Massachusetts Amherst Extension.
If the affected panels of your siding are easy to remove, doing so will allow the snakes a quick exit before you seal any entry points. Act before temperatures cool, as snakes may curl up inside your siding looking for an escape from the cold. You can capture and remove the snakes yourself in order to relocate them to an area away from your home. Wear protective gloves to prevent against bites, and take care not to harm the snakes during the effort.
Pest control specialists can assist you if you have a large infestation or cannot bear the sight of a snake. They have a variety of traps available and training to legally deal with a pest issue.
Visually inspect your siding for openings through which the snakes can find access. These may be located at the lowest edge of the siding or at spots where insulation has been added and plugs have come loose, leaving a convenient hole. You should also check around equipment, landscaping and other features that butt up against the siding and which may allow snakes to climb higher to find an entry point.
Seal any holes or cracks using expanding foam or another sealant. The Colorado State University Extension suggests sealing any 1/4-inch or larger opening. Fill the holes on a warm day, when temperatures are below 90 degrees F. Snakes are less likely to be hiding under such conditions, so you'll reduce the chances that they'll become trapped inside the siding.
Keep any plants around your home's foundation trimmed so that they do not contact your siding and do not provide ready cover for snakes, allowing them to reach your foundation unseen. Remove any rocks around your home's foundation, and keep mulch to a minimum. Reduce insect populations near your home, as they serve as a main food source of garter snakes. Cutout or plastic prey animals placed around snake-prone areas may help intimidate garter snakes and force them to find a new location.
Never use moth balls to try to deter snakes. Not only will they not work, moth balls are meant to be used in enclosed areas, and the vapors are potentially harmful to humans. The University of Illinois Extension also warns that funnel traps are not worthwhile in reducing snake populations around your home.
- University of Massachusetts Amherst Extension: Snakes of Massachusetts: Common Garter Snake
- Colorado State University Extension; Coping with Snakes; M. Cerato, et al.; May 2006
- University of Illinois Extension; Garter Snakes -- A Gardener's Friend; David J. Robson; June 2007
- Texas Parks and Wildlife Department; Texas Junior Naturalists: Snakes!; July 2009
- United Wildlife Control: Snake Trapping, Removal and Prevention Services
- National Pesticide Information Center; Problem Wildlife in the House; April 2011