Do-It-Yourself: Build a Solitary Bee House

"Male Mason Bee (Osmia)" - Copyright 2007 by Stavros Markopoulos (Creative Commons).
“Male Mason Bee (Osmia)” – Copyright 2007 by Stavros Markopoulos (Creative Commons).
If you want to welcome some of the world’s great garden-helpers to your backyard, you need to build them a nice place to stay. Everyone thinks of bees as living in bee hives because honeybees do and honeybees are easily the world’s most famous bees.

But of the thousands of bee species, only a few make honey and live in hives. The rest are solitary bees.

Maybe the most popular type of solitary bees to have around are Mason bees. They are popular because they do a super job pollinating fruits, vegetables and flowers. They are also very mild and don’t sting unless they are handled roughly or get trapped underneath clothing.

There are more than a hundred kinds of Mason bees in North America. They work and live alone, although they don’t mind nesting right next door to other bees.

Mason bees build nests in long narrow holes that they find already made in their environment. These holes could be hollow plant stems or holes drilled by woodpeckers and insects in wood. The bees use mud to build chambers in the holes, then lay an egg in each chamber. Before sealing up the chamber, they leave a dab of pollen and nectar in each for the larva to eat when it hatches.

When the young bees have matured enough in the spring, they’ll bust out of their mud chambers and eventually come to the front of the hole to warm up a bit before flying off to begin the entire cycle again.

When the bees do fly off, the first thing they’ll be looking for is a home. You can help by building them a solitary bee house.

Following the easy directions below, and with just a little help from your folks, you can build a solitary bee house over the winter and have it in place by March or April. Be sure to mount it solidly somewhere out of the rain facing South or East since the little bees need some sunlight to get them going when they emerge.

And remember, building the bee house is just the beginning of the fun and your research. You’ll need to see who shows up and moves in. Get pictures if you can. And by all means, take notes and hold onto them so you can build on your store of observational knowledge year over year.

Here are some questions to get you started:

  • How many different kinds of bees use your solitary bee house? Simply knowing the number of different kinds is useful, but if you want to dig in and get very, very specific, there’s help: www.DiscoverLife.org
  • How many of the tubes get sealed off with mud? Does one size (diameter) seem more popular with the bees in your neighborhood. Develop a hypothesis about what size tubes will attract the most bees next year. Test it.
  • What kind of mud do the bees use to seal chambers? During periods of high activity, put out trays of different kinds of mud to see if the bees have a preference. Does putting mud close to the bee house increase the trip rate of bees (say, three trip every minute instead of two trips a minute)? By how much?

How to Build a Solitary Bee House

The bundle of hollow tubes you gather will need to be secured and held together. Some people use duct tape; others use a beautiful wooden container of some sort. For our purposes here, we picked a common (and free!) option we had around the house.
The bundle of hollow tubes you gather will need to be secured and held together. Some people use duct tape; others use a beautiful wooden container of some sort. For our purposes here, we picked a common (and free!) option we had around the house. (Recycling, anyone?)

When it comes to hollow tubes, nothing beats bamboo. If you have it growing in your yard, you are set. If you don't, ask around. Most people who have it will be more than glad to let you cut some of their bamboo. When picking the size you need, consider this: to attract Mason bees, you want to aim for a hole diameter that is big enough to insert a pencil in, but not too much bigger.
When it comes to hollow tubes, nothing beats bamboo. If you have it growing in your yard, you are set. If you don’t, ask around. Most people who have it will be more than glad to let you cut some of their bamboo. When picking the size you need, consider this: to attract Mason bees, you want to aim for a hole diameter that is big enough to insert a pencil in, but not too much bigger.


The good thing about bamboo? It is tough. The bad thing? It is tough. You'll need an adult and the appropriate tools to get what you need from your neighborhood bamboo thicket. Luckily, anyone with bamboo growing in the backyard probably already knows how to cut it.
The good thing about bamboo? It is tough. The bad thing? It is tough. You’ll need an adult and the appropriate tools to get what you need from your neighborhood bamboo thicket. Luckily, anyone with bamboo growing in the backyard probably already knows how to cut it.


Use scissors to trim your drink bottle to a length of at least 6 inches.
Use scissors to trim your drink bottle to a length of at least 6 inches.


While trimming the branches off the bamboo, get as close a cut as you can. This will make it easier when you are sliding the tubes in because there won't be obstructions.
While trimming the branches off the bamboo, get as close a cut as you can. This will make it easier when you are sliding the tubes in because there won’t be obstructions.


Cut lengths of bamboo to the same length you trimmed your bottle. It doesn't have to be perfect.
Cut lengths of bamboo to the same length you trimmed your bottle. It doesn’t have to be perfect.


If one of the tubes you are trimming begins to split, don't worry. It will be unusable, but will provide an opportunity for you to investigate the internal structure of the plant.
If one of the tubes you are trimming begins to split, don’t worry. It will be unusable, but will provide an opportunity for you to investigate the internal structure of the plant.


Pack the tubes into your container as tightly as you can. It may take a little effort to work in the final few.
Pack the tubes into your container as tightly as you can. It may take a little effort to work in the final few.


Home, Sweet Home! You'll need to find a South or East facing location out of the rain to place this in the spring. Secure it so it doesn't move around. Keep an eye on it to see what happens.
Home, Sweet Home! You’ll need to find a South or East facing location out of the rain to place this in the spring. Secure it so it doesn’t move around. Keep an eye on it to see what happens.

Fun Phineas Facts

We’ve noted the many good qualities of Mason Bees and said they are non-aggressive and unlikely to cause much trouble in the stinging department. It natural for anyone who has been stung by a bee to suspicious of anything with a stinger. Classification – organizing things into orderly categories – is a basic part of good science, and you can practice on “bees.” Even while running away. The first step is to try to avoid calling everything that might deliver a “bee sting” a “bee.”

Do you mean Bee or Wasp? Or Yellowjacket? Or Hornet? The differences matter, since some stinging insects are classified as flower-lovers and others as predators (although, of course, not of humans!). Here is a link to a good article from the Cooperative Extension service at Colorado State University to get you started thinking about the differences.Wasp-Hornet-Yellowjacket-Bee?

One of the best ways to distinguish between types of flying insects with stingers is to notice where they live. If the insect in question lives in a honey-filled wooden box on a honey farm, that’s an easy one. If it lays eggs in the bee house you construct, that narrows it down, too. Here is an article that has a great chart about other types of insect housing you might encounter. How to Tell the Difference Between the Stinging Wasps.