Bees are an essential part of our ecology. Many of our favorite fruits and vegetables would not grace our gardens and produce shelves without their pollination services.
Though the common notion of a pollinator is the honey bee, our gardens are more likely to be pollinated by one of the hundreds of native wild bees (honey bees are not native to North America). Bumble bees are social, with a number of them living in a ground nest (often such things as abandoned rodent holes), but other wild bees are solitary. They individually lay eggs in cracks, crevices, hollow stems, and the ground. Solitary bees sting very seldom (you really have be hassling them) and their stings are more like a mosquito bite. They are a good bee to encourage in your garden area.
While pesticides such as neonicotinids are causing bee population declines, another pressure is the lack of habitat for wild bees. A pristine, manicured, no-clutter-anywhere lawn is a habitat desert for wild bees. You can, however, easily put together a "bee hotel" that will provide a sheltered nesting area for all sorts of non-ground-dwelling wild bees.
I put this together in a few hours from mostly recycled materials. I set it up in the late morning and a few hours later I saw two species of wild bees using it!
Step 1: Gather Your Materials
You will need:
- box to hold the nesting pieces -- I was lucky enough to find a discarded crate (19 1/2 in wide, 12 in high and 8 1/2 in deep) whose bottom was broken; I simply cut a scrap piece of wood paneling to fit for a new bottom (or back, actually, when set up)
- wood or metal to form a slightly slanting roof that will overhang the front of the nest box, protecting it from rain. The roof for the box I used is 13 in x 22 in.
- a 1 x 2 piece to raise the back end of the roof
- nails to attach the riser and roof to the box
- supports for the nest box -- I had some pallet frames on hand from a previous scavenging run, but similar frames could be constructed from scrap or new 2 x 4.
- nest materials:
- bamboo lengths (I bought a few 4 foot lengths at the dollar store)
- bundles of phragmites (common reed) stems
- untreated (but not cedar or redwood) wood blocks with holes drilled into them
- dry hardwood limbs with extensive cross grain cracks or holes drilled into them
Step 2: Tools
You will need:
- a saw for cutting the wood and bamboo pieces to length
- small pruning clipper to cut the reeds to length
- a drill that has an indicator that you have it vertical or a drill press
- 1/4", 7/32", and 9/64" bits, from 3 to 6 inches long
- a hammer
- a level (for adjusting the base)
- a bench vise or workmate platform to hold the wood pieces you are drilling into
Step 3: Preparing the Phragmites Bundles
Phragmites (common reed) is an invasive species in Ontario and (unfortunately) easily found in damp places that used to exclusively host cattails. With pruning clippers, I cut a half dozen dry reeds down and carefully left the seed heads there. You can also use green reeds.
The reeds are hollow between nodes. I cut to one side of each node to produce a length that was open at one end and closed at the other (by the node).
I cut about a foot of twine, gathered up a handful of the cut pieces with the closed ends together on one side, wrapped the twine around the bundle and tied it tight.
The bundles will be placed in the nest box with the closed ends to the back.
Step 4: Preparing the Bamboo Lengths
Like phragmites, bamboo has nodes with hollow areas between them, but you will need a saw to cut the bamboo.
Cut to one side of each node to get your lengths. Sometimes the "open" end will be filled with pith. A 1/4" or 7/32" drill will get the pith out. For safety sake, secure the length upright in a bench vise or workmate before drilling.
I decided I liked the bamboo pieces loose rather than bundled.
Step 5: Prepare Wood Blocks
Blocks should be from 6 to 8 inches long. You will be drilling into the end grain, but not through the block entirely. Bees will use any distinctive markings around the holes (like tree rings or cracks) to find a hole they've already begun to use. A solitary bee will fill lay an egg, deposit pollen to feed the larva, and seal the egg compartment with its material of choice: usually mud (mason bee) or leaf piece (leafcutter). Then it will go off to collect more pollen and repeat the process. Some of the blocks I reused had been cut with an underpowered saw and consequently had scorch marks over some of the end grain.
A drill press will ensure properly vertical holes. If you are using a hand-held drill, use one that has a vertical indicator on it. This is usually a circle marked on the back end of the drill with a moving bubble underneath it: getting the bubble into the circle means your drill is vertical (see second photo).
I would also highly recommend securing the block in a bench vise or a workmate top as shown here in the first photo. It is certainly far less tiring than holding the block with one hand and definitely safer.
Make sure the holes are finished smoothly. Bees won't enter a hole if it is too large, too small, or something might tear its wings. I would drill a number of holes, loosen the block and shake out and off what sawdust I can, resecure the block and run the drill again in the holes to smooth the entrance and get out any spurs sticking into the hole.
Different species have different body sizes, hence the need to different hole sizes. Leafcutters like 9/64" and 7/32" holes. Mason bees like 1/4" holes. You can have holes of different sizes in the same block.
Step 6: Preparing Dry Limb Pieces
I rummaged through our firepit wood pile for a couple of older pieces. Bark flaked off them, but they weren't rotting.
I cut one in half so it would fit into the box. I added holes to another piece since it didn't have many cracks for the bees to nest in.
Step 7: Attaching the Roof
I cut some scrap aluminum siding to a length that would overlap the upright box sides by an inch or so. I used two pieces, one resting on the other to provide a front overhand of several inches.
To provide slant to the roof to better shed rain, I placed a length of 1 x 2 under the back edge of the roof.
Since the material was aluminum, I used some aluminum nails to secure everything to the box.
Step 8: Situating the Bee Hotel
I have a line of cedar trees along the western boundary of my property. I selected one that receives unobstructed sun from the east. Early morning sun is important to bees to warm them up. The tree provides some shelter from the late afternoon sun (and the hottest part of the day!).
The ground in front of the tree was not very level. I got an 18 inch square patio paver to provide a good level base for the structure and leveled it with a brick under one side.
I placed the pallet frames upright on the paver and the roofed box on top of them.
Nothing is permanently secured in this spot, so I can change it if the location proves unsuitable.
Step 9: Filling the Hotel
Once the holding structure was set up, I filled it with the "units" I had produced.
The multi-dimensional hap-hazard arrangement has its own wabi-sabi appeal, but also provides ample cues to bees returning to a nesting hole they have started.
I returned to the hotel three hours later to find three species using it!
Step 10: An Added Amentity: Water
This is a simple waterer I added below the hotel. I wanted something that would provide water for the bees but not be a place for mosquitoes to lay their eggs.
It is a glass pie plate with a thin layer of sand and a few rocks to provide landing places for bees. The plastic bottle has a hole drilled into the bottom of it from which water drips. Uncap the bottle totally and water runs freely; tighten the cap and the flow slows to a drip. The amount of air entering the bottle through the loosened cap determines the rate of water drips. I can increase it on hot days.
Since it is under the bee hotel, it is protected from being flooded with rain.