Guidelines for storing mason bees

Guidelines for storing early or late spring mason bee cocoons under different climates.

Note- these directions are for Osmia lignaria (early spring mason bees).


Choose method of storage according to your climate, winter conditions and your preference.

(1)  When winter temperatures are mostly above 23 0F   (-5 0C)

Set container of mason bee cocoons into a mason bee house or other wooden structure that protects cocoons from the weather, direct sun and predation.  Follow directions noted on small cardboard box with cocoons.


(2)  When winter temperatures are consistently below 23 0F     (- 5 0C) 

If winters are particularly severe as in eastern and central NA, mason bees can be stored inside a fridge until temperatures are no longer below (-5 0C)

It is best to store cocoons inside a manual defrost fridge. Set container of water inside fridge to maintain 60% humidity.  Every week or so check water level in container and top up if necessary.

If an automatic defrost fridge is used set cocoons into container with a lid. Place a wet paper towel or soaker pad on one side and cocoons on the other side of the container. Then make a pencil size hole in the lid so that air can circulate and mold growth is limited.  Keep temperature above freezing (34-38 0F)   (2-4 0C).

In late winter, when spring is a couple of weeks away set bees out adjacent to nesting tunnels.


(3)   When winter temperatures are consistently above 40F

Mason bees need a minimum of one month of cold winter temperatures.  Refrigerate for a minimum of one month.


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