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Mason Bee Cleaning

Thank you to our renters!

We had a lot of mason bees to clean this fall. We are committed to cleaning each bee cocoon raised through our program in order to promote healthy mason bee populations and eliminate predators. See below for pictures of the cleaning process.

Look out for an email from us over the next few weeks letting you know when you can place rental reservations for next year. 

The bee blocks have been in this temperature-controlled room for the summer. 

We do this to protect them from the parasitic mono wasp that emerges in late June. If the bee blocks are not protected, the mono wasp will burrow in the holes and lay it’s eggs on the developing mason bee. The mono wasp larvae will predate the developing mason bees.

How important is it to bring the bees inside?

Here is a photo of a nesting block that was not returned on time and left out in a backyard all summer. Predators have killed almost all of the developing mason bees inside.

More on mason bee predators here.

Once the bees are fully formed in cocoons, it is time to take them out of the nesting blocks to clean them. We use a machine that extracts the bees from the nesting blocks and deposits them into a bucket so they can be sifted. We also have tools that we can use to manually scrap the bees out of the blocks. They are very sturdy!


As you can see, there is a lot more in the blocks than just bee cocoons. 

After the bees have been sifted, it is time for a wash! The cocoons are waterproof so we soak them in a bleach/water bath for ten minutes before putting them on racks and washing them with the garden hose. We do this to remove the mud plugs, pollen mites, and chalkbrood fungus.


After the wash, the bees are then put in our drying tower overnight and sorted the next day. We put them on a light board and any cocoon that allows light to shine all the way through does not contain a viable bee (bottom left photo). This process is much like candling a chicken egg. The final step is to count and weigh each batch of bees.



Finally the clean bees are put into a walk-in refrigerator to hibernate for the winter season. These are the bees that were grown in your backyards this spring and will be put back into the rental program next year or end up as pollinators on one of the local farms we work with. Every renter has an impact on our food system and you are helping us change the agricultural industry one bee at a time!

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Bee Amazed

Mason bees
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400 Mason bees
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One Mason bee
block can hold
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to pollinate their