Wisconsin pests run on a schedule. Ant colonies wake and send out scouts as the ground thaws. Overwintering queens — wasps, hornets, yellow jackets — emerge in April and May scouting nest sites. Box elder bugs and lady beetles that spent winter in your walls start moving. And the mice that got in last fall are raising spring litters. That schedule is exactly why spring is the highest-leverage season for pest prevention: an hour of sealing and cleanup in April prevents problems that would take real money to fix in August.
Here's the complete checklist we'd run on our own homes, organized so you can knock it out in a weekend.
Start Outside: The Perimeter Walk
Pick the first decent Saturday after the snow's gone and walk the entire foundation slowly, twice — once looking down, once looking up.
Foundation and entry points
- Seal cracks in the foundation and gaps where siding meets it with exterior-grade sealant.
- Stuff gaps around pipes, AC line sets, and cable penetrations with copper mesh or steel wool, then seal over the top.
- Check winter's damage: frost heave and freeze-thaw cycles open new cracks every year, so last spring's pass doesn't count.
- Inspect door sweeps and weatherstripping on every exterior door — including the garage service door. Daylight visible means insects (and mice) fit.
- Check the garage door's bottom seal at the corners, the most-missed entry point on most homes.
Roofline, vents, and screens
- Repair torn window screens and make sure they seat tightly.
- Check soffit, gable, and ridge vents for gaps or torn screening — prime entries for wasps, bats, and squirrels.
- Confirm the chimney has an intact cap.
- Clean gutters. Wet, packed leaves breed insects and rot fascia boards, and moist rotting wood is a carpenter ant invitation.
- Scan eaves, deck rails, and porch ceilings for golf-ball-sized starter wasp nests — in May they hold a single queen and are trivially easy to deal with. In August they're not.
Yard and landscape
- Trim shrubs and tree branches so nothing touches siding or roof — branches are ant and rodent highways.
- Pull mulch back a few inches from the foundation, and keep it under three inches deep. Deep, damp mulch against the house is a pest nursery.
- Move firewood off the ground and away from the house.
- Eliminate standing water: sagging gutters, plant saucers, tarps, kids' toys, that tire behind the shed. Mosquito season starts with the water you leave out in May.
- Clean up under bird feeders and store seed in sealed metal containers.
Then Inside: A Focused Hour
- Kitchen: transfer flour, cereal, pet food, and birdseed into sealed containers; wipe cabinet shelves; fix dripping faucets. Spring ant scouts are looking for exactly two things — food and moisture — and a scout that finds nothing reports back accordingly.
- Basement: run a dehumidifier (aim for under 50% humidity) to make the space hostile to silverfish, millipedes, centipedes, and spiders' prey base. Check the sill plate line with a flashlight for gaps and mouse evidence.
- Attic: one flashlight pass for droppings, nesting material, or daylight showing through the roofline.
- Storage: swap cardboard boxes for lidded plastic bins where you can — cardboard is food, nesting material, and hiding place in one.
Know What You're Preventing
This checklist targets Wisconsin's standard spring lineup: ants (pavement ants and carpenter ants both peak in spring), spiders following the insects, wasp queens establishing nests, and the tail end of winter's rodent activity. If you find droppings, frass piles, or insects you can't name during your walk-through, our pest identification guide will help you figure out what you're looking at — and whether it's a "seal the gap" problem or a "call somebody" problem.
Where a Spring Professional Visit Fits
Even a perfectly sealed home benefits from a spring exterior treatment: a barrier application around the foundation, doors, and windows intercepts ant scouts and wasp queens before they establish, which is far easier than evicting them in July. That spring visit is the anchor of our seasonal home protection programs, followed by summer and fall visits timed to the next waves — wasps and mosquitoes, then mice and box elder bugs.
Run the checklist, seal what you find, and if you'd rather have a professional handle the treatment side — or your walk-through turned up something already moved in — request your spring service. April appointments are the cheapest pest control you'll buy all year.