LEARN: 4. How to Raise Spring Mason Bees

4.3 Release Mason Bee Cocoons

4.3 Release Mason Bee Cocoons

Releasing cocoons simply means placing cocoons into the bee house.

Adult bees will emerge from their cocoons and find a nesting hole to claim on their own, no need to place cocoons into the nesting holes. You can release cocoons once the bee house is installed, the nesting holes are placed, your flowers are blooming, and the temperature is right.

Mason bees hibernate as fully formed adult bees inside of their fuzzy cocoons. Mason bees begin to emerge from their cocoons around 50F/10C and it can take several days to weeks for all of the bees to emerge from their cocoons.

Release mason bee cocoons when you have open blossoms and consistent daytime temps of 55F/13C or warmer. Freezing nighttime temperatures do not affect the bees.

Pro Tip: Extend your bee season by releasing half your cocoons, then waiting a few weeks to release the second half. You can store mason bee cocoons in your fridge while you wait.

  • Release a variety of cocoon sizes. Larger cocoons are female bees, smaller cocoons are male bees. The natural ratio for mason bees is 3 males to 2 females.
  • Depending on the weather, it can take up to three weeks for mason bees to emerge.
  • Make sure all your mason bee cocoons are released by mid-May.

If spring arrives late: If your blooms are not yet open, you can keep the emerged adult bees in the fridge and feed them with a cotton ball soaked in a 1 part water to 1 part white sugar solution.

Clayey Mud is Vital: Mason bees will not nest if they can’t find moist clayey mud nearby. Test your soil for clayey mud by digging a small hole near the bee house. When wet, it should stick together and behave like play-dough. Add Spring Mason Bee Mud Mix if it feels gritty or does not stick together.

Topic Completion

How to Raise Mason Bees


Bee Cocoon Hatchery (cocoons not included)
Add our Bee Cocoon Hatchery to your bee house and protect your mason and leafcutter bee cocoons... Learn More
InvitaBee™ Plus+ Mason Bee Attractant
InvitaBee™ Plus+ Mason Bee Attractant for all mason bees in the Osmia species. Invites mason bees... Learn More
Spring Mason Bee Mud Mix
Spring Mason Bee Mud Mix, 8 oz of dry clayey mud that is perfect for your nesting mason bees. Helps... Learn More