Short answer: Scorpions glow blue-green under ultraviolet light. Walk your home's walls, garage and yard after dark with a UV flashlight and they'll stand out, showing you where they hide and which gaps they use.
What you need
- A UV flashlight, sold at hardware stores and online
- Closed shoes and long tweezers or tongs, never bare hands
- A clear night, ideally an hour or two after dark
Where to look
- The base of exterior walls, along the weep screed
- Block walls, especially the top edges and corners
- Around the garage door and its side gaps
- Rock piles, woodpiles and plants touching the house
- Inside: bathroom walls, closets and corners near the ceiling
What your findings tell you
Several scorpions on the block wall but none on the house means sealing will make a big difference. Scorpions on the house walls near doors or vents show you the exact spots to seal first. Finding them inside on most nights means it's time for treatment and a professional sealing.
Keep the light low and steady. Scorpions on textured stucco can be small and easy to miss.
Common questions
Why do scorpions glow?
A substance in their outer shell fluoresces under ultraviolet light.
Is it safe?
Wear closed shoes, don't touch scorpions, and keep kids and pets back while you look.