One creature no one wants to see stirring around their house? A mouse. But keeping mice away from your house can be a big challenge during the colder months, when your home is much warmer than any nest they can build out in the wild.
Still, it’s important to ensure that you keep mice at bay—as mice can bring diseases, chew through and damage parts of your home, and very quickly multiply to large populations. Fortunately, there are some strategies you can use to make your home much less hospitable to mice in the first place—and to deal with any who do get into your home.
- Theresa Rooney, Hennepin County master gardener and the author of The Guide to Humane Critter Control: Natural, Nontoxic Pest Solutions to Protect Your Yard and Garden
- Emory Matts, Technical Service Manager and Board Certified Entomologist for Terminix
Seal Off Cracks and Gaps
The first defense? Make sure there’s no way mice can get into your home in the first place. And this can be a challenge, as they are small and determined—and can fit into an opening just a quarter inch in size, says Emory Matts, technical service manager and board certified entomologist for Terminix. “A good rule of thumb is if you can fit a pencil into a crack, hole or opening, a mouse can get through it. The mice might not fit through a pencil hole, but their nose and mouth can quickly widen the hole for passage by gnawing it out further.”
Matts recommends using steel wool to pack any openings, then covering it with a flexible elastomeric sealant or caulking. “Avoid using plastic, rubber, wood, or anything else mice can easily gnaw through as sealants.” That includes spray foams. “Mice will chew through the foam and even build nests in the cavities they create.”
And don’t forget the gaps around your doors and windows, where good weather stripping is essential. Make sure you use brush guards and gnaw-proof sweeps, and that the door is well sealed against the threshold when it’s closed. Use weather stripping, such as brush guards or gnaw-proof sweeps, to seal door gaps and window gaps and make sure the sweep on your door creates a seal against the threshold when it’s closed.
Keep the Area Around Your House Clear
Make your house your castle—and put a moat around it. That means leaving at least a foot of blank space between your home exterior and any plantings to make getting to your house a challenge for mice, says Theresa Rooney, Hennepin County master gardener and the author of The Guide to Humane Critter Control: Natural, Nontoxic Pest Solutions to Protect Your Yard and Garden. That bare space leaves them open and exposed to predators—so they will be less likely to brave it.
That means positioning wood piles away from your house (which also helps with air circulation to keep your wood dry), removing leaf piles, and cutting back any plants to keep them far from your foundation. Matts also recommends using pea gravel in these spots, which can help prevent rodents from making burrows there.
Spray a Mouse-Repellent Scent
Strong scents can help repel mice, Rooney says. “Fragrant spices and herbs interfere with a mouse’s sense of smell, which is how they live in their world—they sniff out where food or danger is. If you overwhelm their senses, they can’t judge how safe it is, so they just kind of avoid the area.” Fortunately, a lot of the smells that can repel mice are ones that humans adore, especially this time of year—peppermint works well, along with orange and cloves.
You want to spray the mouse repellent product a couple of times just before the ground freezes, to encourage them to find a different place to live.
Some mouse-repellent sprays can also be used indoors along exterior walls as an extra barrier—just check the label and use as directed.
Consider Putting Down Some Blood Meal
Blood meal is about as unpleasant as the name suggests—it’s dried blood from a slaughterhouse. But it’s super effective as a temporary barrier to mice and other prey animals if it’s sprinkled around your home exterior, Rooney says. (And it will help fertilize your soil where it’s placed, too.
Use a mask and gloves when you apply blood meal—and avoid this tactic if you have dogs (they’ll roll in it) or see raccoons around your neighborhood (they’ll be attracted to it).
Welcome in Some Predators
Make your yard more welcoming for animals that feed on mice, like owls, hawks, and foxes. Those bare areas will give hawks and owls plenty of space to see mouse tracks. A snag or tree perfect for perching can give them the perfect vantage point for stalking mice, Rooney says.
Of course, dogs and cats in your home can also help keep mice away from your home—and handle any that manage to pass through your defenses.
Put Your Fall Mulch Down Late
Mulch can be a cozy home for mice, and provide protection as they eat the roots and seeds you’ve planted. “Don’t make them happy,” Rooney says. She recommends putting down winter mulch only after the ground has frozen, to make your gardens around your home less enticing as a home.
Monitor the Quiet Spots in Your Home
“Mice love quiet, dark, and undisturbed areas,” Matts says. So make sure you’re regularly checking out your storage areas and other less-trafficked spots in your home for evidence of mice.
That’s especially true of areas with a lot of clutter, so decluttering and cutting back on what you have in storage can make it less enticing for mice to nest—and easier for you to spot an infestation if it happens.
Food-based holiday decor, like salt dough ornaments, straw wreaths, and gingerbread house kits can be an ideal way to encourage a mouse invasion and infestation.
One secret weapon for discovery: a simple sprinkle of baby powder. “By applying a very light dusting of baby powder around any areas of concern, you can quickly inspect for the mouse’s foot and tail prints in the dust,” Matts says.
Anything you’re putting into storage over the winter—including a boat or ATV—could also be protected with natural clove or peppermint repellents, Rooney says.
Keep Food Out of Reach
Mice need food and shelter to be thrive, so do your best to keep mice at bay is to deprive them of both as much as possible. Matts recommends the following steps for starving out the rodent population:
- Keep all food, including pet food, in airtight containers. Avoid leaving food out on countertops or in open storage.
- Clean up crumbs and spills promptly. Vacuum floors and wipe down countertops regularly to eliminate potential food sources.
- Do not leave pet food out overnight, and clean up any spilled food or water from pet dishes.
- Remove any fallen fruit or unpicked garden vegetables that can also sustain a mouse population.
- Don’t feed birds or stray animals.
Use Snap Traps
Sometimes, even the best repellent tactics fail to keep mice away from your house. And that’s when traps may come into play. Rooney suggests using old-fashioned snap traps as the most humane option—as they will kill mice immediately. “If you poison something you don’t know where it’s going to end up—in the basement wall where it’s going to stink in your house, or eaten by something else.” Sticky traps need to be monitored closely to avoid subjecting mice to a slow painful death. “That’s just bad karma,” Rooney says.
Call in the Pros
If you’ve found evidence that mice have invaded your space—including black, rice-like droppings, a gnaw marks on your food, or (ick) a mouse sighting, a pro might be your best bet. They can look around your home to see how bad the infestation is and figure out where mice are entering, Matts says. “They can recommend a treatment plan that leverages field-tested integrated pest management solutions.”
That can help ensure that your mouse problem ends as quickly and painlessly as possible.