How to Make Mason Bee Nests
- 1). Drill a number of different sized holes in the wood block by using different drill bits. Holes up to 1/2 inch in diameter and 5 inches deep work well.
- 2). Attach a piece of plywood to the back of each wooden block with nails. This forms a back to make attaching the block to trees or fences easy.
- 3). Secure the nest at least 3 feet up to a south-facing fence or tree with nails.
Source...