Silverfish thrive in humid environments and feed on starchy materials found in almost every home. Getting rid of them naturally comes down to three things: removing moisture, cutting off their food sources, and using repellents or traps in the places they hide. None of these methods work overnight, but a combined approach can clear an infestation within a few weeks and keep them from coming back.
Why Silverfish Are in Your Home
Silverfish need two things to survive indoors: humidity and starch. They require a relative humidity above 75% at warm temperatures, which is why you’ll most often spot them in bathrooms, basements, laundry rooms, and under kitchen sinks. Their gut contains enzymes that digest cellulose, so they feed on a surprisingly wide range of household items: cereals, flour, pasta, pet food, book bindings, wallpaper paste, paper with glue, and starch in clothing.
Understanding this is key because every natural method works by attacking one of those two needs. If you only set traps but leave your bathroom at 80% humidity with a shelf of old paperbacks, you’ll keep catching silverfish indefinitely without solving the problem.
Lower the Humidity First
This is the single most effective step. Keeping indoor humidity between 30% and 50%, the range recommended by the EPA, makes it difficult for silverfish to retain moisture, and their eggs struggle to hatch in dry conditions. A dehumidifier in your basement or bathroom can bring levels down quickly. If you don’t own one, a cheap hygrometer (available for a few dollars at any hardware store) will at least tell you which rooms are problem zones.
Beyond a dehumidifier, small habits make a real difference. Run the exhaust fan during and after showers. Fix leaky pipes under sinks. Avoid drying laundry indoors in poorly ventilated rooms. Move stored boxes off basement floors and away from walls so air can circulate around them. If you can get your home consistently below 60% relative humidity, you’ve already removed the primary condition silverfish depend on.
Remove Their Food Sources
Silverfish are drawn to bookcases, closets, and anywhere they can find paper, clothing, starch, or dry food. A few targeted changes make these areas far less appealing:
- Dry goods: Store flour, cereal, pasta, and pet food in sealed glass or hard plastic containers rather than cardboard boxes or paper bags.
- Paper and books: Move old newspapers, magazines, and cardboard out of damp storage areas. If you’re keeping books in a basement, use sealed plastic bins.
- Clothing: Starched fabrics attract silverfish. Store seasonal clothing in airtight containers or vacuum-sealed bags, especially in closets that tend to feel damp.
- Wallpaper: Peeling or damp wallpaper with exposed paste is a buffet. Re-seal loose edges or remove wallpaper in problem rooms.
Vacuuming regularly along baseboards, inside closets, and behind furniture also removes silverfish eggs and any crumbs they’d feed on.
Build a Simple Glass Jar Trap
You can catch silverfish with a jar, some tape, and a bit of flour. Wrap the outside of a glass jar with masking tape or packing tape so the surface is rough enough for silverfish to climb. Drop a small spoonful of flour into the bottom as bait. Place the jar upright near baseboards, under sinks, or in closets where you’ve seen activity.
Silverfish climb the textured tape on the outside, drop into the jar for the flour, and then can’t escape because the interior glass walls are too smooth to climb. Check and empty the jars every few days. These traps won’t eliminate a large population on their own, but they’re useful for monitoring how bad the problem is and confirming which rooms are most active.
Essential Oil Repellents
Several essential oils repel silverfish by producing scents that interfere with the chemical signals insects rely on to navigate. Cedarwood oil is the most commonly recommended. Its compounds disrupt insect pheromones, making treated areas unappealing. Clove oil works similarly, with its intense spicy scent driving silverfish away from treated spots.
To make a cedarwood spray, combine 1 cup of water with 10 to 15 drops of pure cedarwood essential oil and 1 teaspoon of witch hazel or rubbing alcohol (the alcohol helps the oil mix into the water instead of floating on top). Shake well before each use and spray along baseboards, under sinks, around bathroom fixtures, behind furniture, and inside closets. Reapply weekly, since the scent fades.
For a broader repellent spray, you can combine multiple oils. A mixture of 10 drops each of cedarwood and orange essential oil, 10 drops of cinnamon oil, 5 drops of lemon oil, a quarter cup of white vinegar, and half a cup of distilled water creates a stronger deterrent. Test on a small hidden area first if you’re spraying near unfinished wood or delicate fabrics.
Whole cloves placed in small dishes inside closets or under sinks offer a low-effort option if you don’t want to mix sprays. Replace them every couple of weeks as they lose potency.
Diatomaceous Earth for Problem Areas
Food-grade diatomaceous earth is a fine powder made from fossilized algae. To insects, the tiny particles are razor-sharp: they scratch through the waxy coating on a silverfish’s body, causing it to dehydrate and die. For humans and pets, the powder is nontoxic, but it does require some care in application.
Dust a thin layer into cracks along baseboards, behind appliances, under bathroom cabinets, and inside wall voids if you can access them through electrical outlets (turn off the breaker first). The key word is thin. A heavy pile is less effective because silverfish will simply walk around it, and it kicks up more dust.
Keep it dry. Diatomaceous earth stops working when it gets wet, so it’s best suited for areas that stay dry, like closet floors, attic spaces, and gaps behind bookshelves rather than directly under a leaky sink.
Safety Around Pets and Children
Food-grade diatomaceous earth is considered nontoxic, but the dust can irritate eyes and airways. Pets that walk through it may experience dry or irritated skin, and inhaling the dust can cause sneezing, coughing, or watery eyes. Avoid applying it to pet bedding or anywhere pets lie down. Keep it out of reach of small children, and wear a simple dust mask while applying it. Exotic pets like reptiles are especially sensitive to airborne dust and should be kept away from treated rooms entirely.
Seal Entry Points
Silverfish are flat enough to slip through remarkably small gaps. Caulk cracks along baseboards, around pipes where they enter walls, and along window frames. Pay special attention to bathrooms and kitchens where plumbing creates gaps in walls. Weatherstripping under doors that lead to basements or garages can also reduce how easily they move between rooms.
This step won’t kill silverfish already inside your home, but it limits new arrivals and forces the existing population to encounter your traps, repellents, and diatomaceous earth rather than simply relocating to a new room.
How Long It Takes to See Results
Natural methods are slower than chemical pesticides. Reducing humidity begins affecting silverfish reproduction almost immediately, since eggs fail to hatch properly in dry conditions, but the adults already in your home can live for several months. Most people notice a significant drop in sightings within 3 to 6 weeks when combining humidity control with traps and repellents. Diatomaceous earth works within 24 to 48 hours of contact for individual insects, but reaching the entire population takes time because silverfish are nocturnal and avoid open spaces.
Consistency matters more than any single method. Weekly reapplication of essential oil sprays, keeping humidity below 50%, maintaining sealed food storage, and refreshing diatomaceous earth after any moisture exposure will produce steady results. If you’re still seeing regular activity after 6 to 8 weeks of a combined approach, the infestation may be larger than surface-level methods can reach, and you may need to treat wall voids or crawl spaces more aggressively.