Quick facts
- Size
- Most under 1/2 inch, fishing spiders up to 3 inches with legs
- Looks like
- Brown, gray or black, eight legs, varies by species
- Peak season
- Late summer and fall
- Where in Michigan
- Statewide, especially basements, garages and lakefront homes
- Main risk
- Mostly nuisance, medically important bites are rare
- Risk level
- Low
Signs you have spiders
- Webs in basement corners, window wells and garages
- Large spiders running across floors in late summer and fall
- Egg sacs in corners or on window frames
- Many webs around porch lights and soffits
- Spiders on docks, boathouses and lakefront siding
Common spiders in Michigan homes
Cellar spiders, with tiny bodies and long thin legs, live in basements and crawl spaces and build loose webs in corners. Common house spiders build tangled webs around windows and ceilings. Wolf spiders are larger, hairy hunters that run across floors, usually in late summer and fall. Yellow sac spiders are small and pale and sometimes walk on walls and ceilings at night.
Near lakes and rivers, you may see big dark fishing spiders, sometimes called dock spiders, on docks, boathouses and lakefront siding. They can look alarming because of their size but rarely bite. Lakeshore homes also host many orb weavers and other web builders, since swarms of midges and mayflies coming off the water give them plenty to eat.
Do Michigan spiders bite
Most spiders in Michigan rarely bite people, and most bites that do happen are minor, like a bee sting or less. The northern black widow is found in Michigan, usually in woodpiles, stone walls, sheds and outdoor clutter, and bites are uncommon. Wear gloves when moving firewood or stones and you avoid most of the risk.
Brown recluse spiders are not established in Michigan. An occasional one may arrive in boxes or furniture shipped from southern states, but finding one does not mean a population. Many skin sores blamed on spider bites turn out to be infections or other causes. If a bite gets worse, spreads or you feel ill, see a doctor.
Reducing spiders around your home
Spiders follow food. Cut down the insects and you cut down the spiders. Switch porch and garage lights to yellow bulbs or warm LEDs that draw fewer insects, reduce lighting near doors, and seal gaps around windows, doors and sill plates. Run a dehumidifier in damp basements, since many spiders and their prey prefer moist air.
Vacuum webs and egg sacs regularly, especially in fall when they are most noticeable. Clear clutter and cardboard boxes in basements and garages, and keep storage off the floor. A licensed pro can apply an exterior treatment around foundations, eaves and window wells, following the label, which helps most on lakefront homes and cottages.
What you can do yourself
- 1Vacuum webs, spiders and egg sacs regularly.
- 2Use a dehumidifier in damp basements.
- 3Seal gaps around windows, doors and utility lines.
- 4Switch exterior lights to yellow bulbs or reduce lighting.
- 5Reduce clutter in basements, garages and storage areas.
- 6Wear gloves when moving firewood and stones.
When to call a licensed pro
- You see many spiders indoors despite cleaning.
- Lakeshore homes, boathouses or docks have heavy webbing.
- You think you have found a black widow or brown recluse.
What spiders treatment costs in Michigan
$100 to $300per treatment
Typical Michigan ranges, not quotes. Price depends on home size, the number of areas treated and whether it is a one-time or seasonal service.
Typical ranges, not quotes. See the full Michigan pest control cost guide.
Spiders: common questions
Are there brown recluse spiders in Michigan?
Brown recluse spiders are not established in Michigan. Occasional individuals arrive in boxes, furniture or vehicles from other states. If you think you found one, save it in a sealed jar so it can be identified.
Are there black widows in Michigan?
Yes, the northern black widow is found in Michigan, mostly in woodpiles, stone walls, sheds and undisturbed outdoor clutter. Bites are rare. If you are bitten and have severe pain, cramping or sweating, get medical care.
Why do I see so many spiders in fall?
In late summer and fall, adult male wolf spiders and house spiders wander in search of mates, and many end up inside. Fall invaders like cluster flies also give spiders more food around windows.
Do spider treatments work?
They help, especially combined with sealing gaps, cutting outdoor lighting and reducing insects. Spiders are hard to eliminate completely, so the goal is fewer spiders inside and fewer webs on the house, not zero.
Is a bite on my leg from a spider or something else?
It is hard to tell from the bite alone. Many bites blamed on spiders come from other insects, including bed bugs if bites show up in the morning in rows or clusters. See a doctor for any bite that spreads or looks infected.