Use a drill press with a 5/16ths bit and drill initial holes up the length of your drill bit, just as deep as it will go. This will get you started with the holes and make it easier to get uniform coverage and make it easier for you to use your cordless drill to finish off the job.

If you don’t have a drill press, you can use a cordless drill to drill all the holes. The drill press just enables you to set up completely straight holes.

With a cordless drill, you run the risk of going even slightly sideways and possibly drilling into another bee tunnel. If you don’t have a drill press, don’t sweat it and just keep your holes farther apart to avoid crossing them over by accident.

Either way, put no more than 25 holes in any one house (to avoid confusing the bees), staggered around the block or using a template.

If you can, angle the drill so that the holes tip slightly down to allow for water drainage should water get inside. This isn’t 100% necessary if you provide a cover for the mason bee house. However, it can help keep the mason bee house mold free.

Use the cordless drill with 5/16ths paddle bit finish off holes so that they’re at least six inches deep (longer is ok, too).

Use a piece of electrical tape on the drill bit to mark how deep you want to go into the block; this will ensure that you don’t go too deep and bust through the back. (If you do drill to the back, that’s fine, just be sure to add a back piece so the bees are protected.) The male bees are laid at the front and the females are laid at the back. Drilling deep nesting tubes protects the larvae from birds and the elements, making it more likely that the boys make it out alive to mate with the girls in the spring.

After you’re done drilling, carefully bang out any leftover sawdust.

Paint or draw a design near the entrance of at least half of the holes to help the bees orient to their correct holes. The less time mason bees spend trying to “remember where they parked”, the more time they can spend pollinating.

Use a staple gun to attach a hardware cloth protective cover. Fit the hardware cloth over the front of the mason bee house, slightly curved outward about an inch off the surface to prevent long-beaked birds from eating your precious mason bee larvae.

Hang on a post or fence near your fruit trees with your favorite bracket. We used a pipe strap to avoid puncturing the bee house further.

Be sure to place your mason bee houses out by early spring when the masons are emerging from their winter nests. If you've overwintered** mason bee larvae, be sure to put them out near the orchard to pollinate your fruit trees.