Why spiders settle around homes in Quebec
Spiders don't show up by chance. They're after three simple things: food, shelter and a dry place to lay eggs. A home often offers all three — especially as fall sets in.
From mid-August through October, there's a peak in activity across the Greater Montreal area. The reason is twofold: it's the males' breeding season, and the dropping temperatures push females to look for warmer spots for their egg sacs.
The areas they prefer
- Under eaves and soffits — sheltered, dry, rarely disturbed
- At the corners of windows and door frames — insects drawn by indoor light gather there, making it a perfect buffet
- Near outdoor light sources — streetlights, wall sconces, signs
- In bushes and plantings against the wall — guaranteed moisture and darkness
- On decks, balconies and sheds — corners that are seldom cleaned, with little air flow
Spiders are there because there are other insects. Reducing their pantry (mosquitoes, flies, moths) mechanically reduces their presence.
5 signs you have more than just a casual visitor
An occasional spider is normal — it's even a sign of a healthy ecosystem. Here are the signals that point to a real infestation:
- Several new webs every week in high-traffic areas (front door, deck, balcony)
- Visible egg sacs — small white or beige balls in corners or under outdoor furniture
- Increased presence of other insects nearby (a sign of a well-stocked pantry)
- Webs in unusual areas — under the siding, in window tracks, inside air intakes
- The feeling that it never goes down, even after several cleanings
8 proven methods to prevent them from settling in
1. Reduce outdoor lighting at night
Lights attract insects, which attract spiders. Go for yellow or amber LED lighting (less attractive to insects) and install motion detectors so lights aren't left on all night.
2. Seal cracks and entry points
A spider slips through any gap. Check and caulk: around windows and doors, pipe passages, foundation cracks, exterior siding joints.
3. Clear away webs regularly
A simple broom or a jet of water, once a week in peak season, is enough to discourage spiders from coming back. Focus on ceiling corners, soffits and railings.
4. Keep vegetation away from the wall
Bushes, ivy and climbing plants that touch the wall act as a highway bridge for all sorts of pests. Keep a gap of at least 30 cm between plantings and the facade.
5. Repair screens and air intakes
The smallest hole in a screen or a damaged vent grille becomes an entry highway. Inspect them every spring.
6. Vacuum outdoor corners (deck, balcony, shed)
Regularly vacuum seldom-used nooks, especially after winter and at the start of fall. Empty the bag's contents outside right away.
7. Reduce moisture around the home
Check gutters, foundation drains and areas where water pools. A dry home gets far fewer insects — so fewer spiders.
8. Have a perimeter insecticide barrier applied
This is the most effective method if the infestation is already established. A certified technician applies a residual product around the foundation, under the soffits and at entry points. The treatment lasts several months and also eliminates the insects spiders feed on.
Too many spiders around your home?
A perimeter barrier treatment eliminates existing webs and prevents them from coming back for the season.
Frequently asked questions
Why are there so many spiders around my home in the fall ?
In the fall, spiders look for shelter to spend the winter and their breeding season is in full swing. Sunny walls, soffits and eave corners become their favourite spots. The peak lasts roughly 6 to 8 weeks, from mid-August to mid-October depending on the weather.
Are outdoor spiders dangerous in Quebec ?
The vast majority of species found in Quebec are completely harmless. Bites are rare and at worst cause a local reaction similar to a mosquito bite. Venomous species such as the black widow are extremely rare in our region.
How do I keep spiders from entering the house ?
Seal cracks around windows and doors, repair screens, reduce outdoor lighting at night and regularly clear away webs around the house. A perimeter insecticide barrier applied each spring remains the longest-lasting prevention.
Should I call an exterminator for outdoor spiders ?
If you see several new webs appear every week, if they settle in high-traffic areas or if you are worried about certain species, a professional perimeter barrier treatment is the most effective and longest-lasting solution. It also works on the other insects (mosquitoes, flies) that attract spiders.
How long does a spider treatment last ?
A professional perimeter barrier lasts between 3 and 6 months depending on the weather and the infestation pressure. For optimal protection, a treatment in spring and another in late summer cover the at-risk season.