How to Build a Mason Bee House
There are many pre-made mason bee houses available to buy--either online, in catalogs, or at your local nursery. However, building one of your own takes very little effort and little or no money.

Gather supplies:
Scrap wood (non-treated). This can be a 4x4 block, or 2x6 pieces glued together (glue together on the 6" side of the wood), etc. The goal here is to get some depth.
Drill with 5/16" drill bit
A shingle or other flat piece of wood (for a roof--to protect house from rain and sun)
Drill Holes:
With 5/16" drill bit, drill holes in wood. Drill as deep as possible without going through the other end of the wood.
Drill holes approximately 3/4" apart.
Assemble House:
Once the holes are drilled, attach a shingle to top of roof, overhanging slightly on side of house that contains holes. Hammer in with finishing nails.
Where to Place House:
Because Mason Bees love the morning sun, place your house facing the east to give them morning sun, but protect them from later sun and heat.
Mason Bee houses can be placed on fence posts, trees, the side of your house, etc.
Once you give the bees a place to live, you can either buy some mason bees to get started, or wait and see if nature takes over for you.
Want to learn more about mason bees?
Or the pros and cons of having mason bees or honeybees?