Natural Spider Control: Methods and Facts

Most spiders found in homes are harmless and actually beneficial — they feed on insects including mosquitoes, flies, and moths. According to Penn State Extension, the vast majority of spiders in North American homes pose no health risk. However, their presence makes many people uncomfortable, and a few species (brown recluse and black widow in the US) have medically significant bites.

Why Spiders Enter Homes

Spiders come indoors for three reasons: food (other insects), shelter, and mating. A home with an insect problem will attract spiders because the food supply is there. Other factors include:

• Cracks and gaps around doors, windows, and foundations
• Outdoor lighting that attracts insects, which in turn attracts spiders
• Cluttered areas that provide undisturbed hiding spots — basements, garages, closets, storage boxes
• Firewood stored against the house
• Dense vegetation touching exterior walls
• Seasonal changes — some species move indoors in autumn as temperatures drop

Importantly, the Burke Museum notes that most “house spiders” are not outdoor spiders that wandered in. Many common indoor species have adapted to live in buildings and are rarely found outdoors.

Signs of Spider Presence

• Webs in corners, window frames, basements, and garages — web style can help identify the species
• Spiders spotted on walls or ceilings, particularly in the evening
• Egg sacs, which look like small silk pouches, found in protected corners
• Shed skins, as spiders molt as they grow
• Small prey insect carcasses caught in webs

Natural Control Methods

Reduce Insect Prey

The University of Kentucky Entomology Department emphasizes that reducing the insect population inside a home is the most effective long-term spider control strategy. If spiders have nothing to eat, they will not thrive indoors.

• Switch exterior lighting to yellow or sodium vapor bulbs, which attract fewer insects
• Fix window screens to prevent insect entry
• Address any other insect issues (ants, flies, etc.) to reduce spider food supply

Declutter and Clean

Spiders prefer undisturbed spaces. Regular cleaning and decluttering reduces habitat:

• Vacuum corners, behind furniture, and along baseboards regularly
• Remove visible webs — this is the most direct removal method
• Store items in sealed plastic bins rather than cardboard boxes
• Keep storage areas organized with space between items and walls
• Reduce ground clutter in basements and garages

Vacuuming webs and egg sacs directly is effective. Most home vacuum cleaners will kill spiders drawn into them.

Seal Entry Points

Caulk and seal gaps around:

• Window and door frames
• Where utility pipes and wires enter the house
• Foundation cracks
• Gaps around vents and soffits
• Spaces under exterior doors (install door sweeps)

Weather stripping on doors and windows serves double duty — energy savings and pest exclusion.

Peppermint Oil

Peppermint oil is the most commonly discussed natural spider repellent. Some homeowners report positive results spraying diluted peppermint oil (10-15 drops per cup of water, with a small amount of dish soap as an emulsifier) around windows, doors, and baseboards.

The scientific evidence is limited. A 2017 study published in the Journal of Economic Entomology found that certain essential oil compounds showed repellent effects on some spider species in laboratory conditions, but field data on real-world effectiveness in homes remains sparse.

If used, peppermint oil needs reapplication every few days as it evaporates. Some homeowners report that the initial spraying seems effective but the effect diminishes rapidly.

Chestnuts and Hedge Apples

The claim that placing horse chestnuts (conkers) or hedge apples (Osage oranges) around the home repels spiders is widespread in folk tradition, particularly in the UK. Research from the University of Exeter and other institutions has not found convincing evidence that these items repel spiders when simply placed in a room. Some compounds within Osage oranges do have insecticidal properties when extracted and concentrated, but the whole fruit sitting on a windowsill does not release enough to have a meaningful effect.

Vinegar Spray

Diluted white vinegar sprayed directly on spiders will kill them due to the acetic acid content. As a repellent spray applied around entry points, it provides only temporary effect and leaves a strong odor. Most extension services do not list vinegar as a primary spider control method.

Diatomaceous Earth

Food-grade diatomaceous earth applied in thin layers along baseboards, in cracks, and in undisturbed areas can kill spiders that walk through it. DE damages the exoskeleton and causes dehydration. It works slowly and must remain dry to be effective.

DE is most useful in basements, garages, and crawl spaces where it can be applied and left undisturbed.

Sticky Traps

Non-toxic glue boards placed along walls, behind furniture, and in corners catch wandering spiders. While they do not reduce the overall population significantly, they serve two purposes: directly removing individual spiders and helping identify which species are present and how active they are.

What Doesn’t Work

Ultrasonic repellers: No evidence supports the effectiveness of ultrasonic devices against spiders. Spiders do not hear in the same way insects do, and their sensory systems are not affected by ultrasonic frequencies.

Lavender sachets: While lavender is sometimes listed alongside peppermint as a spider deterrent, evidence is even weaker. Placing dried lavender or lavender sachets in rooms has not been shown to reduce spider activity.

Killing every spider on sight: This addresses individual spiders but does nothing about the conditions attracting them. New spiders will replace removed ones if the environment remains hospitable.

Medically Significant Spiders

Brown recluse and black widow spiders are the two medically significant species in the US. A few points from university extension services:

• Brown recluse spiders are found primarily in the south-central US, from Texas to Georgia and north to Iowa. Reports of brown recluse outside this range are almost always misidentifications
• Black widows are more widespread but tend to stay in undisturbed outdoor or garage areas
• Neither species is aggressive — bites typically occur when a spider is accidentally pressed against skin (putting on a shoe or glove where one is hiding)

If these species are present in a home, professional pest management is the standard approach. Natural methods alone are not considered sufficient for addressing brown recluse infestations, according to the University of Kentucky Entomology Department.

When to Call a Professional

• Brown recluse or black widow spiders are identified (or suspected) in the home
• Spider populations seem unusually high, which may indicate a larger insect problem
• Spiders are present throughout the home despite consistent cleaning and sealing efforts
• Anyone in the household has a medical condition that makes spider bites particularly dangerous

For serious infestations, consult a licensed pest control professional.