How to get rid of silverfish naturally involves a two-pronged approach: eliminating existing pests using non-toxic desiccants like diatomaceous earth or boric acid, and altering your home’s environment by reducing humidity (below 50%) and removing food sources like starch-heavy adhesives, paper, and unsealed dry goods.
Understanding the Silverfish: More Than Just a Nuisance
To defeat an enemy, you must first understand its biology. Silverfish (Lepisma saccharina) are “living fossils.” These wingless insects have existed for over 400 million years, predating the dinosaurs. Their longevity is due to their incredible resilience and minimal requirements for survival.
The Silverfish Life Cycle and Why It Matters
Unlike many insects that go through a larval stage, silverfish undergo “incomplete metamorphosis.” Nymphs look like miniature versions of adults. A single female can lay up to 60 eggs at a time, hidden in tiny floor cracks. Because they can live up to eight years, a small sighting today can escalate into a multi-generational infestation if ignored.
Identifying Damage vs. Sightings
You might see the insect—a shimmering, carrot-shaped creature darting across the bathroom tile—but often, you see the evidence first. Silverfish have “mandibles” designed for scraping. Look for:
-
Irregular holes in book pages or wallpaper.
-
Yellowish stains on white linens or silk.
-
Small black specks (fecal matter) that look like black pepper.
Why Silverfish Pick Your Home (The “Three H” Rule)
Silverfish are not attracted to dirt; they are attracted to conditions. If you have an infestation, your home likely meets the “Three H” criteria:
-
High Humidity: They require 70% to 90% relative humidity to breathe through their exoskeletons.
-
Heat: They prefer temperatures between 21°C and 29°C.
-
Hiding Spots: Dark, undisturbed nooks like attic insulation or behind baseboards.
The Hidden “Starch” Diet
Most people know silverfish eat paper, but their diet is more complex. They seek out polysaccharides. This includes the glue in book bindings, the sizing in high-end clothing, carpet fibers, and even the protein in dandruff or fallen hair.
How to Get Rid of Silverfish Naturally: 5 High-Impact Methods
If you want to avoid synthetic pyrethroids or professional-grade pesticides, these natural methods offer high efficacy when applied with precision.
1. Diatomaceous Earth (The Mechanical Killer)
Diatomaceous Earth (DE) is the gold standard for natural pest control. It consists of fossilized algae (diatoms) with microscopic, sharp edges.
-
How it works: It cuts through the silverfish’s waxy outer coating, causing them to dehydrate and die.
-
Pro-Tip: Use only Food Grade DE. Apply it using a “puff” bottle into wall voids and behind electrical outlets where silverfish travel. A thin, barely visible layer is more effective than a thick pile, which the insects will simply walk around.
2. Boric Acid (The Household Hero)
While technically a chemical, boric acid is a naturally occurring mineral. It is a stomach poison to silverfish.
-
Application: Lightly dust the back of bookshelves and under appliances.
-
Safety Note: Keep away from areas where pets or children may frequent, as it can be toxic if ingested in large quantities.
3. The Glass Jar Trap (The Physical Catch)
Silverfish are excellent climbers on textured surfaces, but cannot climb smooth glass.
-
The Setup: Wrap the outside of a glass mason jar with masking tape (to provide grip). Place a piece of bread or a teaspoon of flour inside.
-
The Result: The silverfish climb up the tape to get the food, fall into the jar, and become trapped by the slippery interior walls.
4. Essential Oil Barriers
Silverfish navigate primarily by scent. Strong botanical oils disrupt their sensory receptors.
-
Cedarwood Oil: Contains cedrol, which is a highly effective repellent.
-
Japanese Cedar or Peppermint: These are excellent for spraying inside “dark zones” like the vanity under the sink.
-
Application: Mix 20 drops of pure essential oil with 200ml of water and a splash of vodka (to emulsify the oil). Spray weekly.
5. Dehumidification (The Biological “Kill Switch”)
This is the most effective long-term natural solution. If you drop the humidity in your home below 50%, adult silverfish will stop breeding, and nymphs will struggle to survive.
-
Action: Run a compressor-style dehumidifier in the basement or laundry room. Ensure bathroom fans run for at least 20 minutes after every shower.
Natural Repellents vs. Natural Killers
It is vital to distinguish between what moves silverfish and what eliminates them.
Step-by-Step Eradication Plan: A Real-World Scenario
Imagine you found silverfish in your home office. Here is how a professional would handle it naturally:
-
Declutter: Move all cardboard boxes. Silverfish love the corrugated glue. Replace them with airtight plastic bins.
-
Vacuum: Use a HEPA-filter vacuum to suck up eggs and adults. Pay special attention to the “wall-to-carpet” junction.
-
Treat: Apply a fine mist of Food Grade DE along the baseboards.
-
Seal: Use clear silicone caulk to seal the gaps between the baseboard and the floor. This “locks” the remaining silverfish behind the wall, where they will encounter the DE.
-
Maintain: Place a small cedar block on your bookshelf to discourage newcomers.
Addressing the Source: Why They Keep Coming Back
If you kill the silverfish but don’t fix the environment, they will return.
Check Your Ventilation
Often, silverfish in the attic indicate a roof leak or poor soffit ventilation. Silverfish in the bathroom suggest a slow leak behind the tiles or a failing seal around the toilet base.
The “Dry Goods” Audit
Silverfish can survive for weeks without food, but they won’t thrive without a starch source.
-
Flour and Sugar: Move to glass or hard plastic containers.
-
Wallpaper: If you have peeling wallpaper, the starch-based paste is a 24/7 buffet. Re-glue or remove it.
Common Myths About Natural Silverfish Control
As an intellectual partner in your pest control journey, I must challenge some common “internet wisdom” that actually fails:
-
Myth: Cinnamon kills silverfish. It doesn’t. While they dislike the smell, it is not potent enough to kill or significantly deter an infestation. It usually just makes your floor messy.
-
Myth: Turning on the lights will make them go away. Silverfish are nocturnal, but they won’t leave your house just because you leave a light on. They will simply wait in the shadows until you go to sleep.
-
Myth: One silverfish is no big deal. Because they are so elusive, seeing one during the day usually indicates a significant population hiding nearby.
Frequently Asked Questions (FAQ)
Are silverfish dangerous to humans or pets?
No. Silverfish do not bite, sting, or carry pathogens that cause disease. Their “danger” is strictly economic—they destroy property, books, and food.
How long does it take to get rid of silverfish naturally?
Natural methods take longer than chemical fumigation. Expect to see a significant reduction in 2–3 weeks, but full eradication (including the hatching of remaining eggs) can take up to 60 days of consistent effort.
Can silverfish crawl into my bed?
While rare, they may crawl into bed if you have high humidity in the bedroom or if you eat in bed (leaving crumbs). They are attracted to the starch in laundered sheets.
Does salt kill silverfish?
Salt can dehydrate silverfish, but it is much less effective than Diatomaceous Earth. Salt also attracts moisture, which can ironically create the humid micro-climate silverfish love.
Why am I seeing silverfish in a brand-new house?
New construction often has high moisture levels in the wood and drywall. Additionally, silverfish are often “moved in” via cardboard shipping boxes used during the moving process.
Final Thoughts: Consistency Over Intensity
The secret to how to get rid of silverfish naturally isn’t a single “magic” spray. It is the combination of environmental management and targeted natural barriers. By lowering your home’s humidity and using mechanical killers like DE, you turn your home from a silverfish sanctuary into a hostile environment.
For broader information, visit Wellbeing Makeover
I’m Salman Khayam, the founder and editor of this blog, with 10 years of professional experience in Architecture, Interior Design, Home Improvement, and Real Estate. I provide expert advice and practical tips on a wide range of topics, including Solar Panel installation, Garage Solutions, Moving tips, as well as Cleaning and Pest Control, helping you create functional, stylish, and sustainable spaces that enhance your daily life.