Most of us are familiar with honey bees who live in colonies. But there are hundreds of species of solitary bees. These bees nest in a variety of holes where they lay their larvae. To attract solitary bees to your yard, garden or orchard, consider putting up bee boxes to attract the females so they will lay their eggs in them. Bee activity drops off in September. As the temperatures grow cooler, bring the bee boxes into a cold, dry storage or garden shed for the winter. In the spring, March or April, take the bee boxes back outside and set them back up before the eggs start hatching out.
Cut a length of 3-inch diameter PVC pipe. Cut the pipe ends at a 45 degree angle. The pipe should measure 12 inches between the two shortest ends of the angle.
Cut a cardboard circle 3 inches in diameter and push it into the PVC pipe so it sits at the very centre, dividing the pipe into two 6-inch sections.
Take 3/8- to 5/16-inch cardboard straws, bend them in half and slide them into both sides of the PVC pipe until the bent end touches against the cardboard disk. Fill up both sides of the pipe with bent straws.
Place the PVC pipe outdoors with the long part of the 45-degree angles at the top. This will act as a roof to keep rain out of the cardboard tubes. Select locations to place bee boxes that are facing south or east. Bees are cold blooded, they require the morning sun to warm them up. Hang them or set them on top of a stacked woodpile.
Solitary bees don't sting and are excellent pollinators. The bee boxes should be at least 4 feet off the ground. There can't be any vegetation in front of the tubes. Place near natural vegetation and in orchards. Purchase cardboard straws at cake decorating supply stores.
If birds try getting at the larvae in the cardboard tubes, place chicken wire over the ends of the PVC pipe. Replace cardboard tubes after the eggs have hatched to guard against infestations of mites and parasites.