For the occasional spider in a corner, no. A broom, a vacuum and some sealing will do more than anything you can buy in a spray bottle — and that is what university entomologists actually recommend.
Call someone when you are finding widow spiders where children or pets go, when webs and egg sacs keep coming back within days of clearing them, or when the activity is in a crawl space or basement you cannot reach or keep dry.
Spiders are the pest people most often over-treat and under-manage. The instinct is to buy a spray. The evidence says the spray is close to the least useful thing you can do.
What you can genuinely handle yourself
Almost all of it, if the problem is ordinary. The recommendations below come from extension services rather than product labels, and they are all things you can do this weekend.
- Knock the webs down. NC State calls a broom or a burst from a garden hose adequate control on its own. This is the primary recommendation, not a supplement to something else.
- Vacuum, don't spray, indoors. Baseboards, corners, behind and under furniture. Soft-bodied spiders rarely survive the trip through the hose, and it removes webs and egg sacs in the same pass. Empty it into a sealed bag and put it in an outdoor bin.
- Seal the way in. Weatherstripping, a proper door sweep, and caulk around window frames and foundation cracks. Clemson's line on wolf spiders is blunt: exclusion is the best strategy.
- Dry out the damp places. Cellar spiders want humidity, and they thrive in heated buildings year-round. A dehumidifier or better crawl space ventilation removes the conditions rather than the individuals.
- Clear the harborage. Move stored boxes off the walls, keep firewood and flowerpots away from the foundation, and cut back vegetation touching the house.
- Change the exterior bulbs. This is the one most people miss. Spiders build where insects gather, and insects gather at white light. Clemson notes that switching exterior white lights to yellow or sodium vapour can indirectly reduce spider numbers.
What DIY does not fix
Three things, and they are worth knowing before you spend money.
Sprays are the wrong tool for spiders
UC IPM is unusually direct about this: insecticides will not provide long-term control and should not generally be used against spiders outdoors. Iowa State says insecticide fogs and sprays are not recommended indoors for spider management, calling them generally ineffective. NC State goes further and warns that outdoor spraying can make pest problems worse by killing the natural enemies that were keeping other insects down.
The reason is simple. A contact spray kills what it lands on and does nothing afterwards. Spiders sit in webs off the treated surface, and a fresh one walks in next week. As UC IPM puts it, control by spraying is only temporary unless it comes with housekeeping.
Egg sacs defeat sprays almost entirely
This one has been measured. A 2016 study in the Journal of Economic Entomology tested six water-based sprays and four oil-based aerosols on widow egg sacs, then used a dye tracer to see what actually got inside. The water-based products reached less than 0.1% of the eggs, and spiderlings emerged at essentially the same rate as from untreated sacs.
Silk repels water. The household spray under your sink is water-based almost without exception, so it beads on the outside of the sac and does nothing to what is in it. If you find a sac, remove it physically.
Some spiders live indoors permanently
House spiders, cellar spiders and one of the yellow sac spiders genuinely breed inside — that last species lays its eggs almost exclusively indoors. These populations sustain themselves with no help from outside, which is why sealing the exterior alone does not clear them.
Worth knowing: most of the spiders you see indoors were never outdoors. They are a distinct indoor-adapted fauna that arrives as egg sacs on furniture and boxes, not marching in from the garden.
When it is worth calling someone
| Situation | Verdict |
|---|---|
| One or two spiders a month, webs in the usual corners | Do it yourself. Broom, vacuum, seal the gaps |
| Seasonal late-summer increase, mostly large wandering spiders | Do it yourself. That is the mating season, and it passes |
| Webs return within days of clearing them | Call. Points at an insect problem feeding them |
| Widow spiders, or smooth cream and spiky sandspur-like egg sacs | Call, particularly near children or pets |
| Egg sacs keep reappearing in the same room | Call. Suggests a breeding population, not wanderers |
| Activity in a crawl space or basement you cannot dry out | Call. The moisture is the actual problem |
| Tiny spiders everywhere despite regular vacuuming | Call. Something is hatching indoors |
Spiders are cold-blooded and are not drawn to warmth — most temperate species carry enough natural antifreeze to survive well below freezing. The late-summer increase is the mating season, and what you are seeing is mature males wandering to find females.
It matters here because it ends on its own. Any remedy tried in September looks like it worked a few weeks later. Before you pay for something, check whether the season simply turned.
What a professional actually does
If the honest answer is that sprays do not work well on spiders, it is fair to ask what you are paying for. The work that changes outcomes is not chemical:
- Identification. Whether you have a medically significant species matters more than the count. Widows need a different response from house spiders.
- Finding and removing egg sacs — including in the crawl spaces, soffits and voids you cannot reach.
- Cutting the prey supply. Spiders follow insects. Treating what they eat is what actually reduces them.
- Exclusion and harborage reduction — sealing entry points, clearing the foundation line, advising on moisture and lighting.
- Recurring exterior web removal, which stops the population re-establishing in the same anchor points.
That is a different service from spraying a perimeter, and it is the one worth buying. If a company's whole answer is a liquid barrier, the research does not support it.
The honest cost comparison
A broom, a decent vacuum, a tube of caulk, a door sweep and a couple of amber bulbs will handle the ordinary case for under a hundred dollars, and you will be doing exactly what the extension services recommend. For most homes that is genuinely enough.
Professional treatment earns its money in three situations: when the species is dangerous, when the harborage is somewhere you cannot get to, and when there is an underlying insect problem you have not identified. Paying for it to remove one spider from a ceiling corner is paying for something a broom does better.
If you decide to call us
Our spider control service covers South Carolina, North Carolina and Virginia, and the work follows the evidence: inspection and identification, physical removal of webs and sacs, prey and harborage reduction, and sealing the gaps. If you want to try it yourself first, where spiders like to hide lists the spots worth checking, and how to identify and remove spider egg sacs covers the part sprays cannot do.
The short version
- Most spider problems are a DIY job. Broom, vacuum, seal, dehumidify, change the bulbs.
- Sprays are the wrong tool. UC IPM and Iowa State both advise against them for spiders specifically.
- Water-based sprays reach under 0.1% of the eggs in a sac. Remove sacs physically.
- Call for widows, recurring sacs, or damp spaces you cannot reach.
- The autumn increase is mating season, not spiders fleeing the cold — it passes on its own.
Further reading: UC Statewide Integrated Pest Management Program publishes free, non-commercial guidance on managing spiders around the home — Spiders (UC IPM).
Frequently Asked Questions
Usually not. For the ordinary case, a broom, a vacuum, some caulk and a change of exterior bulbs will do more than anything in a spray bottle, and that is what university extension services actually recommend. Professional help is worth it when you are dealing with widow spiders, when egg sacs keep reappearing in the same room, or when the activity is in a crawl space or basement you cannot reach or keep dry.
Not well. UC IPM states that insecticides will not provide long-term control and should not generally be used against spiders outdoors, and Iowa State says insecticide fogs and sprays are not recommended indoors for spider management. A contact spray kills what it lands on and does nothing afterwards, so a fresh spider walks in the following week.
Almost certainly not. A 2016 study in the Journal of Economic Entomology tested sprays on widow egg sacs and found water-based products reached less than 0.1 percent of the eggs inside, with spiderlings emerging at the same rate as from untreated sacs. Silk repels water, so the spray beads on the outside. Remove egg sacs physically with a vacuum instead.
Knock the webs down with a broom or a hose, vacuum baseboards and corners to remove webs and egg sacs, seal gaps around doors, windows and the foundation, reduce humidity in basements and crawl spaces, clear clutter and firewood away from the walls, and switch exterior white bulbs to amber or yellow so fewer insects gather for spiders to hunt.
It is the mating season, not spiders escaping the cold. Spiders are cold-blooded and are not attracted to warmth; most temperate species survive well below freezing. The late-summer and autumn increase is mostly mature males wandering in search of females, and it passes on its own. This is worth knowing before paying for a treatment, since almost anything tried in September appears to work a few weeks later.
The parts that change the outcome are not chemical: identifying whether a medically significant species is present, locating and physically removing egg sacs including in crawl spaces and voids you cannot reach, reducing the insect prey that spiders follow, sealing entry points and clearing harborage, and removing exterior webs on a schedule so the population does not re-establish in the same anchor points.