Ophidiophobia is the term for an irrational fear of snakes. "Irrational" is used deliberately in this context because snakes are overwhelmingly beneficial to the ecosystems that they inhabit. Even snakes with dangerous venom will typically only bite humans when substantially provoked. Still, to protect their family and pets, many homeowners wish to take steps to repel snakes form entering their lawn altogether. Luckily, there are several different ways to do that.
Snakes in the Lawn
The snakes that are most likely to take up residence in your lawn is almost completely dependent on the geographic area in which you live. Snakes almost always travel onto lawns in pursuit of a source of food or shelter, or both. Anything that offers shelter from predators and from the elements could be a common snake hiding place. "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," are all examples of these hiding places, according to the University of Massachusetts at Amherst.
There are a great many repellents, both home-made and commercially sold, that have traditionally been used to repel snakes from yards. These include moth balls (naphthalene), sulfur, gourd vines, cedar oil, lime, cayenne pepper spray, sisal rope, coal tar and creosote, liquid smoke, artificial skunk scent, and musk from a king snake, a natural predator of other snakes. Typically, these repellents are marketed to control specific snake species rather than all snakes that may come into your yard.
Unfortunately, none of these repellents seem to be effective at preventing snakes from taking up residence in your yard. The Colorado State University Extension conducted individual tests of all these repellents and others and found none to be effective. The University of Massachusetts Amherst echoed the same conclusions after their own testing, summing up quite plainly that "[t]here are no safe, effective snake repellents capable of keeping snakes away from yards or pools."
Since snakes travel indoors seeking shelter and food, it only stands to reason that an effective way of preventing them from coming onto your lawn is to remove their food sources and sources of food. Remove or, at the very least, frequently check and clean secluded, covered and dark areas in which a snake may seek refuge. Consult local university extension services to fund out the most common snake species in your community and what they eat; limit the amount of snake food on your lawn and you therefore limit the number of snakes on your lawn as well.