Everything You Need to Know Before Keeping Mason Bees

Interested in keeping mason bees? Read on for everything you need to know before starting out!

Where to Place Your Mason Bee House

Tubes and Nesting Trays

Next, you will need to equip your bee-house with tubes or nesting trays. While some people use solid wooden houses with drilled holes for nesting, this type of habitat does not allow cocoons to be harvested and there tends to be significant buildup of debris and disease in the holes after being used for multiple seasons. We recommend selecting nesting tubes or blocks that can be opened, and harvesting, cleaning, and storing your cocoons at the end of the season to ensure bee health and populations for the next year. Some options for tubes to use include natural reeds, cardboard tubes with or without a paper insert, or any rigid and breathable material like printer paper rolled around a pencil and fastened with tape. If you want to lure and promote other native pollinators providing tubes with a range of diameters is a good way to promote habitat for the widest range of native bee and beneficial wasp species. Once cocoons are harvested, however, those tubes will need to be replaced.

You will also need to make sure your bees have the right nesting materials available to seal up their development chambers inside the tubes. Mason bees require mud with a heavy clay texture. If this is not naturally occurring in your area, you can purchase bags of clay-mud to mix and put out for your bees. They are sensitive to the moisture level of the mud, so be sure to water it frequently. If you are trying to attract leafcutter bees, they require leaves or petal material to cut and bring back to the nest. They seem to prefer pea plants, roses, lilacs, and dahlias.

Forage and Nesting Material

Your next considerations will be ensuring that your bees will have plenty of forage and nesting materials within their 300 foot foraging radius. Mason bees, and leafcutter bees, are generalist foragers, meaning they gather nectar and pollen from many types of flowers. Make sure you provide a variety of plants with staggered blooming periods so that they have forage throughout their seasons. Finally, we recommend avoiding hybrid plants. These tend to produce less nectar and pollen, and will not provide a high quality diet for your bees. Visit your local nursery and check out the plant lists from Xerces Society to curate the best garden for your bees and other native pollinators. Also, keep in mind that the best plants for native bees are native plants! Native bees have spent thousands of years co-evolving with native plants so they are best at collecting nectar and pollen from those flowers.

Getting Mason Bees

Once you have your house set up, it’s time to introduce the native pollinators to their new home! You can often purchase cocoons for blue orchard mason bees and alfalfa leafcutter bees through local breeders and quality nurseries. We get our cocoons shipped to us from Crown Bees in Seattle Washington.

We recommend purchasing cocoons and using an attractant at the same time, as it may draw even more local bees to your house. Mason bee cocoons can be released when temperatures reach above 50°F consistently in your area. Place the cocoons on a ledge near the habitat or leave enough space above the tubes and set the cocoons there. Adult bees will emerge conveniently near an ideal nesting site and are very likely to move in.

We recommend releasing your cocoons in two waves. The first half should be released right when optimal temperatures are reached and the second half should follow two weeks later. This will extend your spring pollination season, increasing your garden yields. You can store your cocoons in the refrigerator until you are ready to release the second round.

Male mason bees are smaller than females, and emerge first. They forage for nectar and return to the nesting site to await females. Before releasing portions of your population, make sure you have more small than large cocoons. This will ensure there are enough males for your females to mate with.

End of Mason Bee Season + Harvesting

Mason bee season is over when tunnels are capped with mud. This usually happens by early summer. You can choose to move capped and sealed tubes into a protective and breathable bag to prevent predation and parasitism. Store this bag in a warm location where they will not be disturbed. Otherwise, leave sealed tubes in place and undisturbed until fall cocoon harvest. While your bees may do well on their own and wake up when the next season begins, harvesting and cleaning cocoons is the best way to prevent diseases and parasites from spreading.

To harvest, simply open the tubes or nesting blocks and scrape out nesting materials. Then, sort the cocoons from the debris. Be sure to do this in a cool place—you do not want your bees to wake up early after being moved into a warm house! Any c-shaped cocoons should be separated immediately: these are likely affected by chalkbrood, a fungal spore disease that spreads readily.

Wash the cocoons in a cold water bath. If any chalkbrood was found, add a quarter cup of bleach per gallon of water to kill the fungal spores. Any cocoons that sink in the bath should also be separated and discarded. Keep an eye out for cocoons with small holes. These may have been parasitized by wasps, and should remain separate from the healthy bees.

Cocoons can then be stored in the refrigerator between 30 and 40°F, and should be maintained in an enclosure with around 60 to 70% humidity. Cocoons can be stored like this through the winter, until temperatures break 50 degrees F. At that point, they can be placed outside near their nest to begin another season.

Summary

Overall, increasing native bee populations is one of the best ways to support local ecosystems and increase your garden and fruit tree yields. Keeping mason and leafcutter bees and attracting other native pollinators by providing habitat and forage is an easily attainable and super rewarding experience! Go forth and bee!