Peppermint oil is the most effective essential oil for repelling spiders, with actual lab testing to back it up. In a 2018 study published in the Journal of Economic Entomology, researchers put the internet’s most popular spider repellent claims to the test and found that peppermint oil strongly deterred two out of three spider species, including a brown widow. Lemon oil, despite being the most recommended option online with over a million Google results, had zero effect on any spider tested.
What the Research Actually Shows
The study tested peppermint oil, lemon oil, and chestnuts against three invasive spider species from two different families: the brown widow (a close relative of the black widow), the false widow, and one additional species. Researchers used a two-choice setup where female spiders could move toward or away from each substance.
Peppermint oil worked clearly against two of the three species, discouraging them from settling in treated areas. Chestnuts also performed well, showing repellent effects across the board, with even the least sensitive species (the false widow) tending to avoid them. Lemon oil did nothing. The researchers concluded that lemon oil as a spider repellent is a myth.
This is worth emphasizing because most DIY spider spray recipes online call for lemon or citrus oils. If you’re choosing an oil specifically to keep spiders away, peppermint is the one with evidence behind it.
Other Oils That May Work
Beyond peppermint, research on essential oils as spider repellents specifically is very limited. However, several oils have demonstrated repellent or insecticidal activity against related arachnids like mites and ticks, which share some biology with spiders. These include:
- Cinnamon oil: strong volatile compounds with documented effects on mites and ticks
- Eucalyptus oil: commonly used in insect repellent formulations
- Cedar oil: has shown activity against ticks
- Tea tree oil: active against mites, though it carries significant pet safety concerns
None of these have been clinically tested against spiders in the same controlled way peppermint has. They’re plausible options based on related research, not proven ones. If you want the strongest bet, stick with peppermint.
How Spiders Detect These Oils
Spiders don’t smell the way we do. They pick up airborne chemicals through specialized sensory structures on their legs called wall-pore sensilla. These tiny sensors have pores in their outer shell connected to canal-like structures about 100 nanometers wide, which funnel chemical signals inward to nerve endings. The sensors tend to sit on parts of the legs that don’t touch the ground, positioning them to detect scents drifting through the air rather than chemicals on a surface.
This is why essential oil sprays need to maintain a strong scent to keep working. Once the volatile compounds evaporate and the smell fades, there’s nothing left for the spider’s leg sensors to detect. A dried, scentless residue won’t repel anything.
How to Make a Spider Repellent Spray
A basic peppermint spider spray is simple to make. Mix 7 to 10 drops of peppermint essential oil with about 500 ml (roughly 2 cups) of water, then add a small squirt of dish soap. The soap helps the oil mix with water instead of floating on top, and it helps the solution stick to surfaces. Shake well before each use.
Spray it along window sills, door frames, corners, baseboards, and any crevices where you’ve noticed spider activity. You’ll need to reapply at least once a week, since the scent is what does the work and it fades quickly. In warmer weather or well-ventilated rooms, you may need to spray more often. Some people also add a splash of white vinegar (about a quarter cup per batch), which contributes its own sharp scent, though vinegar hasn’t been studied as a spider repellent on its own.
One practical note: essential oils can leave spots on fabric, carpet, and some wood finishes. Test a small hidden area before spraying broadly on upholstery or near light-colored surfaces.
Pet Safety Concerns
If you have cats or dogs, choosing the right oil matters. Several commonly recommended spider-repelling oils are toxic to pets. Tea tree oil is the most frequently reported cause of essential oil poisoning in animals. Cinnamon oil and eucalyptus oil can also cause serious problems: cinnamon is potentially toxic to the liver, while eucalyptus can trigger seizures. Cedar oil also carries seizure risk.
Peppermint oil is generally considered lower risk for dogs at the dilutions used in a spray, but cats are more sensitive to essential oils overall because they lack certain liver enzymes needed to process them. If you use any essential oil spray in a home with pets, keep animals out of the room while spraying and ventilate the area afterward. Don’t run diffusers for more than 30 minutes at a time, never apply undiluted oils near pets, and store bottles where animals can’t reach them.
What Essential Oils Won’t Do
Essential oils can discourage spiders from settling in treated spots, but they won’t eliminate an existing population or prevent every spider from entering your home. The research showed that oils deter “settlement,” meaning spiders are less likely to build webs and stay in areas with a strong peppermint scent. A spider passing through on its way somewhere else may not be stopped by a fading spray on your window frame.
For homes with medically significant spiders like brown recluses or black widows, essential oils are best used as one layer of a broader approach that includes sealing entry points, reducing clutter (especially in garages, basements, and closets), and keeping outdoor lights off or switched to yellow bulbs that attract fewer insects. Fewer insects near your home means less food for spiders, which is ultimately a stronger deterrent than any scent.