Build a basic mason bee house by using a five-sixteenths-inch drill bit to drill numerous holes into a single block of wood. Ensure the bees have enough space by leaving at least three-quarters of an inch around the center of each bee hole.
Drill holes to depths of around 4 to 8 inches; precision is not necessary. Drilling deeper holes attracts more female mason bees as they prefer space for more offspring, while drilling shallower holes attracts more male bees. Keep in mind that a large number of male bees reduces the population's breeding potential. Attract females by placing a supply of mud, which females use to build their nests, near the finished house. Attach a simple plank or board to the top of the mason bee house to protect the insects from the elements.
You don't have to use high-quality timber for your mason bee nest. Old fence posts, construction scraps and dead tree limbs are just as attractive to the bees as highly decorative or carved blocks. You can paint or stain the exterior of the finished house in any kind of finish. However, avoid using wood treatments such as sealers and preservatives, as many of these chemicals are toxic to the bees.