I’m worried about using mulch near my house for fear of attracting termites. What is the best alternative to leaving a strip of bare soil next to the foundation?
The bad news is that termites are ever-present in all but the coldest climates. The good news: You don’t have to invite them into your home.
The strip of bare soil you’re trying to avoid is actually your best defense against these destructive, wood-eating insects. A study at the University of Maryland showed that termites colonize the moist soil beneath mulches of all types, including non-wood mulches like pea gravel and plastic film. Entomologists report that soil moisture, more than the presence of wood, determines where termites establish their colonies. Because their soft bodies are susceptible to desiccation, termites avoid dry soil.
Your strategy, then, is to keep a “dry zone” a foot or two wide around the house. Contour the ground so it slopes away from the foundation. Install roof gutters and direct the downspouts out into the yard. Keep plants—especially plants that offer a dense cover of foliage—at least a foot from the house. Design landscape beds nearest the house so they can be sustained without supplemental irrigation, and use no more than an inch of mulch in these beds.
Keep a watchful eye out for signs of termite infestation: pencil-thin mud tubes on foundations and walls, the occasional “swarming” of winged adults, and, of course, damaged wood. —Doug Hall