Sustainable System: Mason Bee Condo


I have attached the Mason Bee Condo onto a planter in my front garden. It is facing southeast. There are numerous fruit trees in the area. Note the different colored chambers.

Honey bee populations all over North America, Europe and parts of Asia are in decline due to colony collapse. Many of our cultivated food plants require the pollination services of bees and other insects. Without pollination there will be no fruit.


It is hard to see in this picture but this plum tree is swarming with hundreds of bees of different sizes. It's wonderful to lay under the fruit trees at this time of year and hear the buzz of so many busy pollinators. Take time to watch the dance of life.

One solution to this problem is Mason Bees (Osmia lignaria). Mason Bees are a native species that has been in decline due to destruction of their habitat. With a little help from us they could become a major spring pollinator in our gardens. Building a Mason Bee Condo will help these bees have a place to nest.

Mason Bees hatch out around the time plum or early apple trees come into bloom. The males emerge first and a few days later the females. Males do not pollinate but mate and die. The females find a suitable nesting site.

Mason bees naturally nest in insect holes or hollow reeds but we can help them out by setting up a condo. The female proceeds to collect nectar and pollen which she brings back to the nest. Then she lays one egg and builds a wall of clay. The nectar and pollen will feed the growing larvae. She will repeat this process about thirty times during a five to six week period.

We can help out the female by placing a small bowl of damp clay near the condo. The bee will use this clay for her masonry work. The female can control the sex of her eggs and only lays male eggs at the end of the chamber so they will emerge first.

Mason Bees like to live together but do not want to share chambers with other bees. Coloring the ends of the chambers different colors helps the female find her nest. A female will fill about two chambers during her laying period. You do not have to buy Mason Bees for your condo. If you build a condo, your local bees will happily move in!

If you would like more information about attracting Mason Bees to your garden please see Blue Orchard Bees. There are plans for making your own condo and numerous videos on how you can care for your bees and condo. If you would like to get more involved with your bee’s life cycle there is a video on how to clean mites out of your bee cocoons using sand.


This picture was taken on July 28, 2012. I had just returned from a short holiday. I was pleased to see some bees had moved-in while I was away! Note the clay plugs in fourteen of the holes.