Solitary Bees

When to Release Mason Bees

You got your mason bee house, put the tubes in, and found the perfect location for it.  Now what? Now is the best part – it’s time for the bees!  At this point, you can try to attract some mason bees to the house, or you can order mason bee cocoons.

If you order cocoons, like I did, you need to know when to release mason bees.  To release mason bees means to place them in the bee house.  This needs to be done at the right time, under the right conditions. 

Read on to learn when to release mason bees. 

What You Need for Mason Bees

Before you release your mason bees, there are a few things you need to have in order.  You need a proper mason bee house, nesting tubes, mason bee cocoons, and clayey mud.

Mason Bee House 

Before releasing your mason bees, make sure your mason bee house is set up properly in a good location.  The area should not get too much wind, rain, or direct sunlight.  Under the eaves of a house is an ideal location.  

Facing the bee house south or southwest is ideal because the morning sun will get the bees up and flying nice and early.  Crown bees has some really nice mason bee houses, and Amazon has several as well.

Nesting Tubes

Nesting tubes are important because this is where the bees will lay their eggs. The 2 types of tubes commonly used are natural reeds or cardboard. Natural reeds are strong and water resistant.  Cardboard tubes are disposable and easy to open to harvest cocoons.  

No matter what type of nesting tube you use, just make sure that it is the proper width.  Mason bees prefer tubes with an 8mm diameter. 

Mason Bee Cocoons

Of course you will need some mason bee cocoons. If you raised mason bees last year, you can use the cocoons that you harvested then.  Or, you can order them online and have them delivered to you.  

I ordered my mason bee cocoons from Crown Bees.  The process was really easy.  You just choose the date that you want your cocoons to ship.  I received my cocoons 2 days from the shipping date, and the shipping was free.  

Clayey Mud

Mason bees use mud to construct their nests, so it is important to have a good mud source nearby.  They prefer to use moist, clayey mud.  To achieve this, you can dig up a patch of soil and spray water over it.  Or, if the soil in your area is not adequate, use a mason bee mud mix. 

When to Release Mason Bees


If you want to know when to release mason bees, check the temperature.  You can release your coocons when daytime temperatures are around 55F/13C or warmer.  As a rule of thumb, if you see dandelions blooming, it is warm enough to release mason bees.  

You should also check the weather forecast for the week before releasing your bees.  If a lot of rain is coming, it may disrupt the amount of pollen on the flowers. Bees also need the sun to warm up their bodies to fly, so make sure there won’t be an extended period of cloudy days. 


assorted color flowers

When you see budding branches and blooming flowers, it may be time to release your mason bees. It’s important to have a lot of springtime blooms when your bees are released so they have something to eat. 

What if Spring Comes Late?

Ideally, your mason bees should all be released by mid May.  However, in the event that Spring comes late, or you are in the midst of a storm, you can store your cocoons in the fridge for the time being. Use a Humidibee Cocoon Humidifier to prevent the cocoons from drying out.

How to Release Mason Bees

To release your mason bees, simply put the cocoons in the bee house.  They do not need to go in the tubes.  You can leave a space at the top of the bee house and set the cocoons on there.  You can also put the cocoons in a small container to protect them from birds and rain.  

To extend your spring pollination season, release your mason bees in 2 waves. Do the first half when the above qualifications are met.  Then, do the second half 2 weeks later.  

It can take up to 3 weeks for mason bees to emerge from their cocoons, so you need to be patient. First the males will emerge and wait close by for the females.  Once the females arrive, they will mate and claim a nesting hole.

At first, it may appear that your bees have flown away, but you may be surprised to see a mud capped nesting hole a few days later. To see if bees are in your bee house, shine a flashlight into the nesting holes at night.  You may be able to see the bees resting inside of them.


You know when to release mason bees when the following conditions are met: Daytime temperatures must be consistently 55F or warmer and there must be budding branches and blooming flowers.