To all those who have purchased cocoons or filled nesting tubes of OMBs from me, this is a reminder to keep them refrigerated with about 70% humidity until time to place them outside. If keeping them outside in an unheated building in the northern states, they should be protected from hard freezes. You can place them in a rodent proof container filled with straw or shredded paper. I think the fridge's crisper with a moist sponge is still the best place to store them, assuming the wife will allow it.
The time for placing the bees outside will depend upon your location and climate. The emergence should be timed to coincide with fruit tree blooming.
In my area this is late March but will be later in more northerly locations.
Be certain to have at least 6 new empty tubes for each filled tube you locate outside so the females can lay and increase your population of mason bees.
I hope this answers some of the more common questions that have come to me. I try to answer each individual inquiry, buy I may have missed a few.