Tiny Red Dots on the Windowsill? Don't Squish Them.
Found tiny red dots on your window that smear like blood? They are Clover Mites. Learn why you shouldn't squish them and how to build a gravel barrier.
Smearing a tiny red dot across a windowsill often triggers a panic about biting insects. In reality, that bright red streak isn't blood from a bite—it's just the body pigment of a Clover Mite (Bryobia praetiosa). These are strictly plant feeders, thriving on well-fertilized lawns, not humans or pets.
Why They Enter Homes
Clover mites are nuisance pests driven by temperature. They tend to invade structures during early spring or late autumn when the temperature changes rapidly.
They are attracted to sun-exposed surfaces. The south and west sides of a house, particularly concrete foundations, absorb heat and become a magnet for mites migrating from the cooler grass. Once on the wall, they accidentally crawl through window screens or cracks in the siding seeking shelter.
The Gravel Barrier Solution
Killing them inside is messy and ineffective; squishing them stains paint and fabric, while sprays only kill the ones currently visible. The most effective control method is environmental.
Clover mites struggle to cross dry, rough surfaces. A "plant-free zone" of about 18 to 24 inches around the foundation of the house acts as a physical barrier. By removing grass right up against the wall and replacing it with pea gravel or mulch, you create a dry moat that the mites cannot easily traverse. This significantly reduces the population that makes it to the window level.