How to Successfully Raise Mason and Leafcutter Bees (Crown Bees Part 2)

How to Successfully Raise Mason and Leafcutter Bees (Crown Bees Part 2)

This is the second of three guest blogs by our pollinator-supporting friends over at Crown Bees of Woodinville, Washington.

Mason and leafcutter bees are solitary hole-nesting bees. They carry pollen loose and dry on their hairy bellies, which makes them effective pollinators. Both types of bees are easy to raise, fun to watch, and safe for families with pets. 

Both bees can be raised under similar conditions. However, each bee type is active during a different season. Mason bees emerge from their cocoons in early spring and are superior pollinators of apple, pear, almond, cherry, blueberry, and strawberry plants. Leafcutter bees emerge from their cocoons in early summer and are great pollinators of squash, melons, peas, and other summer fruits and vegetables. Both bees are generalists and will visit a variety of flowers in your garden.

All Crown Bees products arrive with detailed instructions. The bees need consistent daytime temperatures: 55°F for mason bees and 75°F for leafcutter bees. Remember to think about when your plants are blooming and to pick your dates so the bees arrive shortly before flowers start to open.

Tips for Bee Raising Success

Tips for Bee Raising Success

Install the bee house and place cocoons.

Choose a southeast facing wall that receives morning sun and afternoon shade. Bees are cold-blooded, so they need the sun’s warmth to get going. Install the house at eye level so that you can easily watch activity. Installing the bee house is easy. It’s like hanging a picture or putting up a birdhouse. Mason and leafcutter bees have a short flying range of 300 feet, so ensure that your Garden Tower® system is near the bee house.

Place out nesting materials. Mason bees prefer the larger 8mm holes and leafcutter bees prefer smaller 6mm holes. You can use the same bee house for both bees since they are active during different seasons. Just swap out the nesting materials for each bee species.

Once the nesting materials are in the house, place the cocoons on top and towards the back. We want the bees to crawl over their new homes as they emerge so that they know where to come back. Make sure you don’t place cocoons into direct sunlight!

Female mason bees require moist, clayey mud for building protective walls between nesting chambers. If your soil is too sandy or has too much humus, you should supplement with the dry mud mix included in your BeeWorks kits. A texture of soil or mud that sticks to itself when pinched with your fingers is best.

Bring in filled nesting materials and protect from pests.

Bring in filled nesting materials and protect from pests.

The BeeGuardian bag protects against ants and parasitic wasps.


Female mason bees only actively fly for 4 to 6 weeks. Once a female is done filling her nesting hole with next year’s bee eggs, she caps the end of the hole with a thick layer of mud. It is important to protect filled and capped nesting materials from ants, birds, and parasitic wasps. Protect the filled materials by placing them into a fine mesh bag called the BeeGuardian. Store in a warm garage or shed that has similar temperatures as the outdoors. The mason bee larvae need summer warmth as they feed and develop.

Female leafcutter bees also only fly for 4 to 6 weeks but because leafcutter bees often develop quickly and emerge in the same summer they were laid, their season of activity is longer. By the end of summer, they no longer fly. That is when you should remove filled leafcutter materials with which to fill your BeeGuardian bag through the fall and winter. Store in a cool garage or garden shed. Because of their delicate nature, you should not harvest leafcutter cocoons until early spring.

Harvest cocoons in late fall or early spring.

Harvest cocoons in late fall or early spring.

Harvesting cocoons from lake reeds is easy and ensures your cocoon’s health.


In the Pacific Northwest, mason bees spin their brown waterproof cocoons by the beginning of October. Harvesting cocoons helps maintain bee health by removing three big pests: pollen mites, chalkbrood (fungal infection), and parasitic wasps (typically a species called monodontomerus). Mason bee cocoons can be washed in a mild bleach solution to remove chalkbrood spores.

Leafcutter bee cocoons should not be harvested until early spring, around the time that mason bees are placed. Leafcutter cocoons are not waterproof, and leafcutter bees hibernate as larvae, so their cocoons are more delicate. Harvesting leafcutters in the spring can help mason bees that have nested inside of the leafcutter cocoons a chance to emerge.

Return healthy cocoons to your garden for additional pollination.

Mason bee cocoons should be stored in your refrigerator to ensure that they overwinter at a consistent temperature. Crown Bees’ Humidibee container (included in BeeWorks kits) is designed to keep mason bee cocoons humid but not too wet.

In spring, when daytime temperatures are consistently above 55°F and your spring flowers are blooming, set your harvested and cleaned mason bee cocoons out.

You will need to incubate leafcutter cocoons in your home. Plan for it to take about 6 weeks at an indoor temperature of 70°F.

Raising mason and leafcutter bees only takes about an hour per year, and you’ll probably end up spending more time standing next to their bee house watching them come and go.

Ensure your garden’s pollination

Raising mason and leafcutter bees will help your garden grow more and grow better fruit and vegetables. Many flowers need to be visited many times in order to grow fruit at all. For example, a pear flower needs to be pollinated 30 times to make fruit! A flower that is properly pollinated will grow fruit that is rounder, fuller, and healthier. Adding a different bee species to your garden or farm can increase your yield by twenty-four percent! All of the effort that you put into your garden will be rewarded when you raise gentle, solitary hole-nesting bees.

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