Do perimeter sprays actually get rid of spiders?

Not reliably. Texas A&M's School IPM program states plainly that interior and exterior insecticidal sprays are "generally ineffective at reducing spider populations, but may provide some repellency." Spiders are arachnids, not insects, and residual chemistry designed for insects doesn't affect them the same way. UC IPM adds that such sprays "will not provide long-term control and should not generally be used against spiders outdoors" — sealing and sweeping do the real work.

Is it safe to spray for spiders around pets?

Keep pets off any treated surface until it's fully dry, and be aware that permethrin-based products carry the same cat-toxicity risk documented for tick and flea products — cats cannot safely metabolize permethrin and can develop tremors or seizures from exposure (ASPCA). Since spider sprays offer limited benefit to begin with, many households skip broad spraying entirely and rely on sweeping, sealing, and prey reduction instead, which carries no pet-poisoning risk at all.

Is it legal to DIY spider spraying in New Hampshire?

Yes, on your own property, using consumer-labeled products. Applying pesticides on property you don't own — even common over-the-counter products — requires an NH commercial applicator license under RSA 430:33. Restricted-use products are automatically restricted in NH per rule Pes 701.02 and require licensed application regardless of whose property it is, so a homeowner spraying their own house and yard with general-use products is on solid legal ground.

What do pest control professionals actually use on spiders?

Licensed applicators lean on void dusts and targeted residual treatments in wall voids and entry points combined with exclusion work, rather than broad yard-wide spraying — Texas A&M School IPM notes this combination outperforms spraying alone. The bigger part of a professional visit is usually web and egg-sac removal plus sealing entry points, not chemical application, since that's where the actual, lasting control comes from.

Do sprays kill spider egg sacs?

Largely no. The Burke Museum's arachnology program specifically notes that spider egg sacs are "relatively impervious to pesticides" — the tough silk casing protects the eggs inside from contact insecticides even when directly sprayed. Physically removing and disposing of egg sacs by vacuum or broom is far more reliable than trying to spray them, and it's the step most homeowners skip.

Will spraying my whole yard fix a spider problem?

No. UC IPM states that insecticides "will not provide long-term control and should not generally be used against spiders outdoors." Spiders repopulate an area quickly from surrounding habitat, and broad outdoor spraying also risks aquatic toxicity from runoff into nearby streams or storm drains. A better outdoor lever is reducing exterior lighting, which draws in the flying insects spiders are actually hunting.

Why do spiders keep coming back after I spray?

Because the underlying draws — entry gaps and an available insect food supply — are still there after the spray dries. Spraying kills only spiders directly hit at the time of treatment; it does nothing to close the cracks they're entering through or to reduce the insects they're hunting indoors, so new spiders from the surrounding area simply move back in within days or weeks.

Are essential-oil or plant-based spider sprays effective?

These are EPA minimum-risk (25(b)) products with short-lived contact effects at best — useful for a quick spot treatment on a spider you can see, but not a durable control strategy. They share the same core limitation as conventional sprays: no meaningful residual effect on an arachnid, and no impact on egg sacs or the entry points that keep letting new spiders inside.

ChemicalSpiders

Chemical Spider Control: Why Sprays Mostly Don't Work

TL;DR

Residual insecticide sprays are WEAK against spiders — a distinction worth understanding before you buy a can. Spiders are arachnids, not insects, and don't react to residual chemistry the way insects do: sprays kill only what they directly contact, egg sacs are largely impervious, and spiders repopulate quickly. Physical control (sweeping webs, sealing gaps, reducing prey insects) does the real work; chemicals play only a minor, supporting role.

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NH License #782664Family-owned since 2017Updated Jul 2026

Why sprays underperform
Spiders are arachnids; residual insecticides were designed for insects and work poorly on them
Burke Museum (arachnology).
Egg sac resistance
Spider egg sacs are relatively impervious to pesticides
Burke Museum.
What sprays actually kill
Only the spiders directly contacted by the spray — 'and that's about all'
Burke Museum.
Outdoor spray guidance
Insecticides will not provide long-term spider control outdoors and should not generally be used
UC IPM.

The honest verdict

Does this actually work?

Residual sprays are weak against spiders because they're arachnids, not insects, and don't respond to residual chemistry the way sprays are designed for; physical exclusion and prey reduction do the real work.

Low — Rarely Works

Evidence: Texas A&M School IPM: interior/exterior sprays are 'generally ineffective at reducing spider populations, but may provide some repellency.' Burke Museum: sprays kill only spiders directly contacted, and egg sacs are 'relatively impervious to pesticides.' UC IPM: outdoor insecticides 'will not provide long-term control and should not generally be used against spiders outdoors.'

Works when

Void dust is applied inside wall voids/attics as part of a broader exclusion plan
A visible spider is spot-treated directly, not relied on for lasting control
Spraying is paired with — not substituted for — sealing gaps and removing webs/egg sacs
Exterior lighting and prey-insect populations are reduced alongside any treatment

Fails when

Whole-yard or whole-house spraying is expected to solve recurring spider activity
Egg sacs are sprayed instead of physically removed
Spraying substitutes for sealing entry points
Sprays are applied near blooming plants or waterways without regard for runoff

At a glance

Spiders aren't insects — and that's why sprays disappoint

How it works

Easy DIY

Contact pyrethroids kill spiders they directly hit but leave a weak residual against them compared to insects, since spiders don't groom or move across treated surfaces the way many target insects do; void dusts persist longer in wall voids and attics where spiders shelter, giving them a slightly better track record than surface sprays.

Vital stats

Time: Minutes to spot-treat; ongoing for the mechanical work that actually controls spiders
Best for: A minor, supporting role — spot-treating a hunting spider you can see, or applying void dust in an attic/crawlspace as part of a broader exclusion and prey-reduction plan. Not a standalone fix for recurring spider activity.
Cost: Low for spot sprays and void dust; free inspection / same-day service for a full exclusion visit

Perimeter pest sprays are built and tested against insects. Spiders are arachnids, and multiple extension and arachnology sources agree they simply don't respond to residual insecticides the way ants or roaches do. Texas A&M's School IPM program puts it plainly: interior and exterior insecticidal sprays are "generally ineffective at reducing spider populations, but may provide some repellency." The Burke Museum's arachnology program is more blunt — a spray "will kill the spiders contacted directly by the spray, and that's about all," and even a heavily sprayed egg sac usually survives.

That doesn't mean chemicals are useless — void dusts and targeted spot treatments have a real, if narrow, role. But if you're hoping a spray will solve a recurring spider problem on its own, this page's job is to say clearly: it won't. What actually works is removing webs and egg sacs, sealing entry points, and cutting the insect population spiders are hunting.

Step by step

How to do it

Remove webs and egg sacs first
Vacuum or sweep away webs and egg sacs before any chemical treatment — this removes what sprays can't reliably kill anyway.
Tip: Removing webs forces remaining spiders to cross any treated surface, improving contact odds.
Seal cracks, gaps, and install door sweeps
Close the entry points spiders and their prey insects use to get inside — foundation cracks, gaps around utility lines, and door/window gaps.
Caution: This step does more for long-term control than any spray.
Reduce prey insects and exterior lighting
Cut outdoor lighting that draws flying insects, and address any indoor insect population — UC IPM notes this reduces spiders more than spraying does.
Tip: Switch exterior bulbs to yellow/sodium-vapor, which attracts fewer insects.
Only then, spot-apply a labeled residual or void dust
Apply a thin band at the foundation and entry points, or dust in voids/attics — not a whole-yard application.
Caution: Read and follow the label; the label is the law.
Monitor with sticky traps
Place sticky monitors along baseboards to track whether activity is actually declining after your exclusion and treatment work.
Tip: Rising catches point to an unaddressed entry point or prey source, not a need for more spray.

What you need

Tools & materials

Vacuum with extension wand
Physically remove webs and egg sacs
Empty the canister/bag outside afterward
Cobweb duster
Reach high corners and eaves for web removal
Use before any treatment, not instead of it
Sticky monitor traps
Track spider activity along baseboards over time
Non-chemical, useful for confirming a plan is working
Sealant and door sweeps
Close entry points for spiders and their insect prey
The highest-value single tool on this list
Gloves
Safe handling during web/egg-sac removal and any spot treatment
Especially important if a widow or recluse is suspected

Products & actives

What to use — the label is the law

Product classes only — never a dosage. Always read and follow the product label.

Residual perimeter liquids

Active class: Pyrethroid class (bifenthrin, deltamethrin, lambda-cyhalothrin)

Limited repellency/knockdown at foundation and entry points as a supplement to exclusion

Read and follow the label — the label is the law; not effective as a standalone spider control

Contact aerosols

Active class: Pyrethrin/pyrethroid class

Kills spiders directly hit, especially on webs during removal

Read and follow the label

Void dusts

Active class: Residual dust class

Longer-lasting control in wall voids and attics where spiders shelter

Read and follow the label; apply only in voids, not living spaces

Plant-oil sprays

Active class: EPA minimum-risk 25(b) class

Low-residual spot treatment on a visible spider

Read and follow the label; short-lived contact effect only

Stay safe

Safety first

Pets
Caution
Keep pets off treated surfaces until fully dry; avoid permethrin-based products around cats specifically, since they can't safely metabolize permethrin (ASPCA).
Children
Low risk
Keep children away from treated surfaces until dry, and store any product out of reach.
Pollinators
Caution
Don't spray blooming plants; follow the EPA bee advisory box directions on the product label for any outdoor application.
Waterways
Caution
Pyrethroids are toxic to fish and aquatic insects — avoid runoff into streams, ponds, or storm drains from any outdoor spray.
Applicator
Low risk
Follow label PPE guidance; gloves are advisable when handling webs or egg sacs, particularly if a widow or recluse is suspected.

Avoid these

Common mistakes

Why this method fails in practice.

Whole-yard spraying instead of targeted spot treatment or void dust
Relying on sprays instead of sealing gaps and sweeping webs
Spraying egg sacs and expecting them to die (they largely don't)
Over-spraying indoors when the real fix is reducing prey insects and entry points
Ignoring exterior lighting that keeps drawing in the insects spiders hunt

New Hampshire context

Chemical spider control in New Hampshire

Most spiders found in New Hampshire homes — cellar spiders, cobweb/house spiders, wolf spiders, and occasional widows — are nuisance species rather than medically significant ones; New Hampshire lacks established brown recluse populations. Spiders peak indoors in late summer and fall as they seek shelter before the first hard frost — Manchester's arrives roughly October 19 (50%) to October 29 (80%), Concord's around October 3, and Keene's around October 1. Restricted-use products and treating property you don't own both require an NH commercial applicator license (RSA 430:33; Pes 701.02).

Peak season

Late summer through fall, as spiders move indoors ahead of the first hard frost

First-frost anchor: Manchester first hard frost ~Oct 19 (50%) / Oct 29 (80%); Concord ~Oct 3; Keene ~Oct 1 (NOAA 1991–2020)

Restricted-use products require NH licensing under RSA 430:33 and Pes 701.02; treating property you don't own requires a commercial applicator license regardless of product.

Extension guidance statewide favors exclusion and prey reduction over yard-wide spider spraying, consistent with UC IPM and Texas A&M School IPM findings.

This method targets

Pests this applies to

When to call a pro

Spider Pest Control with Anchor

Because chemistry does relatively little against spiders on its own, most recurring spider problems actually point to something else — an unsealed entry point or a heavier-than-normal indoor insect population. Anchor's licensed technicians combine void treatment with exclusion work and web/egg-sac removal rather than defaulting to a spray-only visit.

Call us when…

Recurring heavy webbing despite your own sweeping and sealing efforts
A suspected black widow or brown recluse indoors
Spider activity that suggests a larger indoor insect-prey problem
You want void treatment done correctly in hard-to-reach attic or wall spaces
Spiders returning after DIY spraying — usually an entry-point or prey issue, not a chemical one

Spider Pest Control

free inspection; same-day service across southern and central New Hampshire.

Get a free inspection Learn about the service

Keep them out

Sweep webs and egg sacs regularly rather than relying on sprays
Seal foundation cracks and install door sweeps
Cut exterior lighting that draws prey insects, and reduce indoor clutter where spiders hide

Common questions

Frequently asked

Sources & further reading(6)

[1]
Texas A&M AgriLife — School IPM Action Plan for Spiders
Interior/exterior spray ineffectiveness, void dust + exclusion recommendation
extensionverified 2026-07-13
[2]
Burke Museum — Spider Myths: Myth of the Spider Infestation
Residual insecticide limits on arachnids; egg sac pesticide resistance
academicverified 2026-07-13
[3]
UC IPM — Spiders Pest Notes
Outdoor spray limits; prey-reduction guidance
extensionverified 2026-07-13
[4]
Texas A&M — Biting and Stinging Pests: Spiders
General spider biology and IPM approach
extensionverified 2026-07-13
[5]
ASPCA — Feline Toxins to Steer Clear Of
Permethrin toxicity in cats
medicalverified 2026-07-13
[6]
EPA — Pollinator Protection / Bee Advisory Box Labeling
Bee advisory label requirements for outdoor sprays
govverified 2026-07-13

Written & reviewed by

Verified

Daniel Brady

NH-Licensed Pesticide Applicator · License #782664 (NHDAMF, RSA 430)

Daniel Brady is the New Hampshire–licensed applicator behind Anchor Pest Services, a family-owned pest control company serving the Manchester area since 2017.

Verify license

Anchor Pest Services

When spiders won't quit, we will.

Same-day service across Southern New Hampshire. NH-licensed #782664. Family-owned since 2017. We diagnose the pest, then treat it the right way — with a satisfaction guarantee.

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Keep Exploring

Chemical Spider Control: Why Sprays Mostly Don't Work

Works when

Fails when

Spiders aren't insects — and that's why sprays disappoint

How it works

How to do it

Remove webs and egg sacs first

Seal cracks, gaps, and install door sweeps

Reduce prey insects and exterior lighting

Only then, spot-apply a labeled residual or void dust

Monitor with sticky traps

Tools & materials

Vacuum with extension wand

Cobweb duster

Sticky monitor traps

Sealant and door sweeps

Gloves