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Learn how to Store & Return Your Mason Bee Nesting Block


Mason bee season is starting to come to an end. Each hole that is capped with mud contains 5-7 developing mason bees. You may even have quite a few partially filled holes in your nesting block. Some of the mason bees you hatched have even chosen to nest in other locations in your yard, helping to boost the local population of native bees in your area! Mason bees start their lives as eggs that are laid in the spring, hatch into larvae, and will spend the summer developing and finally pupating into fully grown bees wrapped in their own cocoons.

Each mason bee larva is perched on its own food source (pollen and nectar) and is separated by a wall of mud. This is the chamber the bee will develop inside of until we harvest the cocoons in the fall to clean them.

How To Return Your Mason Bee Blocks  This Year

If you received a shipping return label with your rental, and are no longer seeing bee activity, it is time to store the mason bees for the summer. They are too fragile to be mailed back right now! Gently remove the nesting block from the outer house and store it in your garage or basement with the holes facing up where it can remain undisturbed for the summer. If you want, you can store it in the shipping box the bees arrived in. This will protect them from parasitic wasps and high summer temperatures.

What about the PVC tube(s)? Please take the cap off of the PVC and empty the contents of the tube into your garbage. You’ll return the tube(s) along with your bee rental as we will clean and reuse them next season.
If you planned to return in person we will be offering several sites for no-contact return. Due to COVID-19 we have had to alter our plans significantly because many of our host businesses are still not fully open to the public. If you are unable to travel to one of our return sites, you can opt in to storing the bees at your house for the summer (by gently removing the nesting block from the outer house and storing it in your garage or basement with the holes facing up), and return them to us in the fall just prior to cleaning season. See below for our drop box options.

If you already received leafcutter bees from us, you can release them now. They are contained inside of the wood block and will emerge when day time temperatures are consistently in the mid to upper 70s. We will send you an email in September when the mason bees are fully formed in cocoons and secure enough to be sen

Mason Bee Return Drop Box Options
Your bee kits have a barcode on the back linked to your information. We will be able to check you back in by scanning the back of your bee block. If you plan to rent bees next year, you can hold onto the outer black house. Please note we will not be able to coordinate leafcutter bee pick up with our drop boxes. Since we are not able to offer drop off locations all throughout the Pacific NW, you can opt into storing the bees for the summer and return them to us in the fall.

Drop boxes will be available from June 1st-June 14th during business hours of each respective business. Please practice safe social distancing.

Bellevue Nursery
842 104th Ave SE Bellevue, WA 98004 Map

21 Acres 
13801 NE 171st St Woodinville, WA 98072 Map

Christianson’s Nursery
15806 Best Rd. Mt Vernon, WA 98273 Map

We are not able to offer in person pick up of leafcutter bee rentals this year. If you have already reserved leafcutter bees and planned to pick them up in person, please click here to opt in to have your leafcutter bees mailed to your home.

If you would like to rent leafcutter bees for the summer and do not yet have a reservation, click here to sign up. We have limited leafcutter bees available so you’ll want to sign up now to get them for summer.

Thank you for your flexibility this year and for supporting solitary bees! With any questions, please contact us at [email protected] or give us a call at 206-954-2175.  

Join our Rent Mason Bees Community Facebook Group to learn more about how to best support solitary bees in your backyard! 

Reader Interactions


  1. Scott Anderson says

    I made mason bee houses out of wood blocks. They’re about filled up now. Should I take them down and store them once filled? it’s only late April, but store them until next spring? I cannot access the holes to remove larva.

    • Thyra McKelvie says

      In the future we encourage you to use nesting material that can be pulled apart so your cocoons and nesting material can be cleaned. We’ve seen an increase in houdini flies and pollen mites which could harm all your bees the following spring when they’re hatched. As soon as your block is totally full. Gently remove them and place in an unheated garage or shed for the rest of the summer with the holes upright. The larva are still forming and eating the pollen, then will spin a silk cocoon and hibernate over winter, so be very gentle with them right now. Next sprig, place them in a box with holes upright and poke a few holes in the box where the bees can emerge. Get new nesting material that can be pulled apart and then your mason bees will nest in the clean new holes. You can dispose of your old block and may want to burn it to remove all the pests that could be inside. Houdini flies lay thousands of eggs. Pollen mites, unfortunately, crawl onto the mason bee when it emerges.

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Bee Amazed

Mason bees
visit up to
flowers a day
400 Mason bees
do the work of
honey bees
One Mason bee
block can hold
bees per acre
to pollinate their