Most American homes see a seasonal spider surge twice a year — a warm September when males roam for mates, and a cold March when they retreat indoors to escape freezing garages and sheds. Effective indoor spider control is less about killing the spiders you see and more about denying them the two things they need: a steady food supply and undisturbed hiding spots. Nail those two variables and the population collapses inside two or three weeks. Fail on them and you can spray every corner of the house monthly without making a dent.
Part of our Windows & Doors guide — explore the full guide →
Identify What You Are Dealing With
Of the 3,000+ spider species in North America, only two widespread groups pose a real medical risk: the brown recluse (found primarily in the central and southern US) and the black widow (found nationwide, most often in garages, woodpiles, and crawlspaces). Every other house spider — wolf spiders, cellar spiders, jumping spiders, common house spiders — is harmless and actually eats pest insects you do not want. Identify before you spray.
Brown recluse have a distinct violin marking behind the head and only six eyes instead of the usual eight. Black widows are glossy black with a red hourglass on the underside. If you confirm either, skip DIY and call a licensed pest control operator.
Step One: Cut the Food Supply
Spiders do not move into your home for the climate — they follow prey. Every spider you see indoors is there because enough flies, gnats, moths, or other insects are present to feed it. Reducing indoor insects by 80% reduces spider populations by a similar margin within a month.
- Fix window screens: Any tear larger than 1/8 inch lets flies and moths in
- Replace exterior bulbs with warm yellow or sodium-spectrum LEDs: White LEDs attract 10x more insects
- Seal pantry food in hard-sided containers: Denies food to the flour moths and weevils that fuel spider food chains
- Empty trash daily and close lids tight
- Run a dehumidifier in basements: Target 40-50% RH; most household pests struggle below 50%
Step Two: Eliminate Hiding Spots
Spiders prefer dark, undisturbed corners: basements, garage storage, under beds, behind large furniture, and in the gaps behind baseboards. A deep one-time clean cuts their habitat dramatically.
Vacuum along baseboards, under and behind every piece of furniture, inside closet corners, and along the top edges of wall-hung cabinets. A HEPA canister vacuum like the Shark Navigator Lift-Away ($180-$260) pulls spiders, webs, and egg sacs in one pass. Empty the canister outside into a sealed bag immediately — eggs can still hatch in a plastic liner.
Step Three: Seal Entry Points
Caulk and weatherstripping are the two cheapest, most effective indoor spider control tools you own. Walk the exterior of your home once each fall and seal any gap wider than 1/8 inch.
- Exterior caulk (GE Silicone II, DAP Dynaflex 230): Around window trim, siding penetrations, and foundation cracks
- Door sweeps: Brush-style sweeps on garage and exterior doors
- Foam backer rod plus caulk: For any gap wider than 1/4 inch
- Hardware cloth (1/4 inch mesh): Over attic vents, dryer vents, and crawlspace openings
- Weatherstripping: Replace any door or window gasket showing compression damage
Natural Repellents That Actually Work
Peppermint oil is the one natural repellent with replicated study backing — spiders avoid concentrations above 3%. Mix 20 drops of pure peppermint essential oil (not fragrance oil) with 8 oz water and 1 teaspoon dish soap in a spray bottle. Treat baseboards, window sills, door frames, and garage corners twice a month.
White vinegar, chestnuts, and citrus peels are popular folk remedies with mixed evidence. They may deter briefly but wear off in days. Skip them as your primary strategy.
Chemical Sprays When You Need Them
For heavy infestations, a residual spray labeled for spiders creates a chemical barrier lasting 60-90 days. Ortho Home Defense Max (bifenthrin, $12-$18 per gallon), Bayer Suspend SC (deltamethrin, $45-$60 per 16 oz concentrate), and Syngenta Demand CS (lambda-cyhalothrin, $65-$85 per 8 oz) are the three most effective products sold to homeowners.
Spray the exterior foundation perimeter up 2-3 feet, around every window and door, and inside basements along baseboards and sill plates. Read the label — some products are unsafe around cats or aquariums. Always ventilate treated spaces for 2-3 hours before reoccupying.
Sticky Traps for Monitoring
Glue boards like the Catchmaster 72MAX ($8 for a 6-pack) placed under beds, in closet corners, and behind furniture catch wandering spiders and reveal which rooms have active populations. Check weekly. A trap that catches 10+ spiders in a week means the source is nearby — look for an egg sac within 5 feet.
Egg Sac Removal
A female spider can lay a sac containing 100-400 eggs. Remove sacs as soon as you see them. Vacuum directly, or knock them into a sealed plastic bag with a paper towel. Silk egg sacs are usually tan or cream, round to oval, and roughly the size of a pea.
When to Call a Professional
Hire a licensed pest control company if you spot brown recluse or black widow, if sticky-trap counts stay above 10 per week after a month of DIY measures, or if you have a crawlspace or attic infestation you cannot safely access. A typical quarterly perimeter treatment runs $95-$180 per visit and includes a year-round warranty from companies like Orkin, Terminix, and Aptive.
