It's also a fun DIY project that can be completed with little or no money, depending on what tools or resources you have available.

What is a Tunnel-Nesting Bee?

Six Commonly found Mason and Leafcutter Bee species found in Michigan
Commonly found Mason and Leafcutter Bee species found in Michigan - Image Credit 1

The guests you will be welcome to your bee hotel are tunnel-nesting or solitary bees. These primarily include carpenter bees, leafcutter bees, and mason bees.

These tunnel-nesting bees are solitary creatures that don't live in hives or produce honey. The females are fertile and take care of building her nest and foraging alone.

It is not uncommon for some tunnel-nesting females to share nests, which are referred to as communal bees. Although they share space, they live entirely independent of one another.

Within the tunnel, females will construct brood cells of mud, plant resins, and other plant materials. Each cell is provisioned with pollen and nectar. The female then lays her eggs and seals the cell.

Although tunnel-nesting bees do not produce honey or beeswax, they are responsible for pollinating many plants, including the fruit and vegetables we eat.

Step 1 - Choosing a Location

We recommend choosing the location for your bee hotel before you start planning or construction. This way, you know what size bee hotel the site can accommodate.

Stem bundle bee hotel mounted in wooden frame in garden
Stem bundle bee hotel mounted in wooden frame - Image Credit 2

Here are some factors to consider when choosing where to put your bee hotel:

  • Find a location protected from rain or moisture, wind, and insect predators.
  • According to the USDA National Agroforestry Center, bee hotels should be constructed four feet off the ground. If you have kids or animals, make sure to place the bee hotel out of reach.
  • In addition to pollination, tunnel-nesting bees secrete a cellophane-like substance to build their nests. For the bees to be able to feed and build their nests, ensure there is a diversity of plant species, soil, and trees close by (within a few hundred yards).

If you have an outdoor shed, mounting the bee hotel against a wall with shelter from the eves could be a good idea.

If you do choose to mount the bee hotel on a building or shed, make sure it's away from regular foot traffic, pets, and children.

Step 2 - Designing and Construction

Now that you have selected your location, you can start planning the construction of your bee hotel. There are many ways to build a bee hotel. We'll cover some of the easiest and cheapest types of bee hotels.

It's important to remember the bee hotel will live outside. Possibly through some harsh weather and temperature changes. Make sure your construction will hold up through the seasons.

For example, a piece of string holding everything together might rot after a wet spell.

Wherever possible, try to upcycle items you have lying around to reduce waste.

One crucial step in designing a bee hotel is to make sure you can safely remove nesting materials while broods are waiting to hatch. We'll explain the purpose of this in "Using Emergence Boxes" later in this article.

Designing Your Bee Hotel

When planning to build a bee hotel, you need to consider who your guests might be. If you are accommodating a specific species, you will need to ensure you have the correct tunnel diameter.

To accommodate a wide range of tunnel-nesting bees, you will need holes between 3/32 and 3/8 inches (2mm and 10mm) in diameter and 3 to 6 inches (76mm to 152mm) deep.

Wooden block bee hotel with multiple sized holes
Wooden block bee hotel with multiple sized holes - Image Credit 3

The depth of the hole should be relative to the width. So if you have a large hole, make sure the tunnel is deep enough for an insect of that size to move around and build a nest.

Tunnel-nesting bees select nests that are closed off on one end. If you are using materials like reeds or straw, make sure you cover the holes at one end with a solid opaque material. Like a block of wood, for example.

Another thing to consider when designing your bee hotel is predators. For example, you don't want to construct something easy for a bird to land on and reach the tunnels.

Placing a wire mesh over the front of the entrance to your bee hotel makes it difficult for birds and other predators to reach the nests.

Stem Bundle Bee Hotel

Stem Bundle Bee Hotel with upcycled tin cans and gardening scissors
Stem Bundle Bee Hotel with upcycled tin cans - Image Credit 4

The stem bundle bee hotel is the quickest and easiest way to build a bee hotel. You are essentially mimicking a stack of reeds or plant stems that a bee might find in the wild. The stem bundle bee hotel can be mounted in a tree or under the eves of a roof.

Simply take a bundle of stems and tie them together. Use a piece of wire or something durable to bundle the stems.

An alternative to wire or string is you could place the stems in an old ice cream tub, water bottle, tin can, glass jar, or similar container.

Using a plastic container is a great way to upcycle and prevent plastic from entering the environment.

Here are some popular materials to build a stem bundle bee hotel:

  • Bamboo is probably the best option for a bee hotel. Bamboo stems are incredibly durable and weatherproof.
  • Reed is another natural material you can use to construct your bee hotel.
  • PVC pipe is excellent for bee hotels because it's durable and will last for several years.
  • Plastic or paper straws are perfect for small tunnel-nesting bees.

Wooden Block Bee Hotel

Wooden block bee hotel made using logs
Wooden block bee hotel - Image Credit 5

If you want to get more creative, a wooden block bee hotel is a fun DIY project. Wood is more natural-looking, and you can create a bee hotel to match your garden's aesthetic.

Another benefit of the wooden block bee hotel is you can design a structure to place anywhere in the garden with protection from weather and predators.

Again, try to find wood you can upcycle. An old log or a piece from your woodpile would make an excellent bee hotel.

Make sure you don't use treated wood. This wood is often treated with chemicals to kill insects, which is not what you want to do!

Use a 4 x 4-inch block for small bees or a 4 x 6-inch block if you want to accommodate larger bees. If you wish to attract a wide range of tunnel-nesting bees, then a 4 x 6-inch block would be the better option.

You will need several size drill bits to hollow out rooms for your guests. When drilling the holes, remember not to go all the way through. You want each hole to have a back wall.

Follow these guidelines for drilling your holes:

  1. Drill holes ranging from 3/32 and 3/8 inches (2mm and 10mm) in diameter.
  2. For holes less than 1/4 inch (6mm), drill 3 to 5 inches (76mm to 127mm) deep.
  3. For holes wider than 1/4 inch (6mm), drill holes 5 to 6 inches (127mm to 153mm) deep.
  4. The holes should be 3/4-inch apart. This is measured from center to center of each tunnel as well as from the sides of the block.

With a wooden bee hotel, you also have the option of designing different compartments with specific materials to attract more insect species. For example, you can have a chamber for stem bundles, a solid block of wood with holes, and a batch of straw or wood shavings for tiny bees and insects.

Bee hotel designed to accommodate multiple sized bees and insects
Bee hotel designed to accommodate multiple sized bees and insects - Image Credit 6

Step 3 - Bee Hotel Maintenance

Like human hotels, bee hotels require maintenance to keep the space safe and habitable. If left unattended, bee hotels will attract parasites and disease that will harm or kill broods.

Also, the provisions and larvae left by female tunnel-nesting bees are excellent sources of protein for other insects, birds, and animals. Here are some measures you can take to protect and maintain your bee hotel.

Protecting a Bee Hotel from Weather

Protecting against the elements is crucial for the survival of your bee hotel. One downpour can flush out all your nests, killing the bees and their broods.

Construct your bee hotel to prevent this and then check regularly to make sure the nest is staying clean and dry.

Direct sunlight can also be a killer. The heat will literally cook the insects and their broods in their nests.

The wind can also wipe out a bee hotel. If you live in a windy area, make sure you provide enough cover and make sure to check regularly that your defenses are adequate.

Protecting a Bee Hotel Against Ants

One of the biggest threats to a bee hotel is ants. With the ability to climb anywhere and everywhere, ants can clean out a bee's nest in less than a day.

Use ant traps, sticky spray, or even duct tape at the base of your bee hotel to prevent ants from getting to the nest. Monitor the bee hotel regularly to monitor the effectiveness of your ant defenses.

Protecting a Bee Hotel from Birds and Other Animals

Bee hotels are an all you can eat buffet for birds and other animals. They can comfortably sit and gorge themselves on the protein-rich larvae.

The best protection is wire mesh placed over the front of the bee hotel. About 1/8 inch from the tunnels should be enough to prevent most birds and animals from reaching the nests.

Bee hotel protected against birds using wire mesh
Bee hotel protected against birds using wire mesh - Image Credit 7

Monitor your bee hotel at different times of the day to see if predators can get the nests. Especially in the mornings and early evening when birds are most active.

Using Emergence Boxes

If everything goes to plan, you should only need to clean your bee hotel once a year.

Using emergence boxes is a great way to increase the survival of the hatching brood. An emergence box can be made using any sealable container (like a plastic bin) with a 3/8-inch hole for bees to exit.

In late winter or early spring, remove the stems and woodblocks from your existing bee hotel and place them in the emergence box for the broods to hatch safely.

Replenish the bee hotel with fresh stems, blocks, and other materials. Place the replenished bee hotel outside the emergence box so when the bees exit, they have a clean, sanitized nest to move into.

Once all the bees have vacated the old nest, you can clean and prepare the materials for the following year. If you are using wood or other organic materials, you may need to dispose of the old nest. Parasites might be living inside the pores, making it difficult to disinfect.

Conclusion

As I'm sure you may have noticed, building a bee hotel is not as straight forward as throwing some materials together. It may seem like a lot of work, but it's really very simple.

Bee hotels just need to be checked on from time to time with some small annual maintenance. If you're a DIYer, building a bee hotel will be easy and a lot of fun.

This is a fantastic opportunity to upcycle and use what's lying around rather than going buying new materials. If you don't have anything at home, search your neighborhood, or ask friends and neighbors for any materials they might want to get rid of.

Have you built a bee hotel? Please share your experience, tips, or pics you might have in the comments below. Also, feel free to ask any questions.

References

Solitary and communal bees - Wikipedia

Carpenter Bees - Wikipedia

Leafcutter Bees - Wikipedia

Mason Bees - Wikipedia

USDA National Agroforestry Center - Enhancing Nest Sites For Native Bee Crop Pollinators

Upcycling - Wikipedia

Other Research References

Xerces.org - Tunnel Nests for Native Bees

Michigan State University - Building and Managing Bee Hotels for Wild Bees

Image Credits

Header/Featured Image - Fotyma via Envato Elements

Image Credit 1 - Michigan State University - Building and Managing Bee Hotels for Wild Bees - Page 7, Tunnel Nesting Bees of Michigan

Image Credit 2 - REN51 via Twenty20

Image Credit 3 - Michigan State University - Building and Managing Bee Hotels for Wild Bees - Page 4, Wood block drilled with holes of various diameters to attract a diversity of stemnesting bees.

Image Credit 4 - REN51 via Twenty20

Image Credit 5 - ErgΓΌn Karahan via Twenty20

Image Credit 6 - Viki2win via Envato Elements

Image Credit 7 - Anterovium via Envato Elements