How to Set Out Spring Mason Bee Cocoons

How to Set Out Spring Mason Bee Cocoons


Releasing, or setting out, spring mason bee cocoons is easy and there are a few guidelines that you should follow to keep the bees happy and healthy.

Remember that mason bees need morning sun, plenty of open blooms, and nearby clayey mud to nest!


• Spring mason bees need a minimum daytime temperature that is warming to 55F/13C (don’t worry about nighttime temperatures) and they need open blooms to feed.

• Chewing out of cocoons takes time. You should allow for this time in your planning for cocoon release. Fluctuations in weather can slow the bees’ emergence from their cocoons and it can take up to two weeks (or longer) for the bees to emerge.

• Ensure an open and ready source of pollen. Look to your fruit trees for the bloom stage known as ‘popcorn’ and dandelions are a good food source while fruit blooms are opening. Set your mason bee cocoons out ahead of the peak bloom.

• Apply InvitaBee Plus+ pheromone attractant to the front of your clean and easy to open 8mm size nesting holes. Mason bees like to nest where mason bees have nested before. Spray InvitaBee Plus+ a few mintues before setting out your mason bee cocoons. Use nesting holes that are easy to open in the fall to remove healthy cocoons from common pests and diseases.

For first-time mason bee raisers:

Simply set the small cardboard box with the lid open into your bee house. Place the small cocoon box on top of and towards the back of your nesting holes.

For seasoned mason bee raisers:

When releasing last year’s cocoons, we recommend staggering the release of your cocoons.

• Split your cocoon population into groups of 1/2 or 1/3, making sure to have a mix of small (male bees) and large (female bees) cocoons in each group. Female bees must mate before they can start nesting.

• Set a group of cocoons into the bee house in a cocoon hatchery tube and wait a week or two before setting another group out.

• Staggering cocoon release is a good strategy when you have more than one type of fruit tree that you want to pollinate. 

Always make sure to keep mason bee cocoons out of direct sunlight.

Setting cocoons on top of and towards the back of the nesting holes keeps them protected from sunlight and it helps the bees get to know their new home.

Pro Tip:

It’s best to set cocoons out in the morning or early evening. In the morning, the bees will have more time to warm up, emerge, and fly. In the evening the bees will get a good night’s rest and will be ready to go the next day.

After you release cocoons, relax and try to remember to be patient as you watch for mason bee activity at the house. Female mason bees need to emerge, mate, get to know the area to find pollen and mud, and return to the bee house. Mason bees start building their nests at the back of the nesting hole and it is very hard to see that far into their nesting hole. If you must, you can shine a flashlight into the bee house to look for shiny mason bee bottoms or faces.

Ensure a Clayey Mud Source

Soon after releasing your mason bee cocoons, make sure the female bees have the moist clayey mud they need to build their nests. Female bees won't nest if they can't find mud nearby. Learn the 3 Easy Ways to make mason bee mud here.

Want to know more? Check out our Learn page about releasing mason bee cocoons.

Have fun raising mason bees this spring!


Mason Bee Mud Mason Bee Mud


    • Related Articles

    • Making Mud for Mason Bees

      How do I make mud for mason bees? In the spring, female mason bees protect each nesting chamber with a wall of clayey mud. If mason bees can't find clayey mud nearby their bee house, they won't nest and will fly away. These bees are named after ...

    • Spring Mason Bee House Setup Tips

      Spring Bee House: Setup Tips from the Pros Bees are cold-blooded and they need the warmth of the sun to get going. Your bees will have more time to fly and build their nests if they have a warm place to live that faces the morning sun. They also ...

    • Spring Care for Wild Bees

      How do I take care of my bee hotel in the spring? Wild hole-nesting bees, depending on their season, may start flying in the spring.  • Springtime wild bees likely spend the winter as fully-formed adults, all they need to do is chew out of their ...

    • Mason Bees: Remove and Protect

      Why do I remove and protect mason bee nesting materials in the summer? Blue orchard mason bees (Osmia lignaria) and horned-face mason bees (Osmia cornifrons) both only produce one generation of bees per year. Knowing this fact makes it easier for us ...

    • When to harvest cocoons

      Mason bees overwinter as adult bees and should be harvested between October-December. Read how to harvest mason bee cocoons here. If you forgot to harvest in the fall, see how to shift bees from old nesting-holes to new here. Mason bee cocoons ...