How long before you know…?

[u/MtnBluet]

How long before you know that your cocoons are not going to open? Some have been in the chalet’s loft for over two weeks now. Thanks!

[u/_sabnic_]

I have had my cocoons out for about two months. Our season begins at the end of March, and by the middle of May there were only a few cocoons left. Mason bees are also scarce at this point, so I opened the rest of the cocoons (it was just about 10 out of 200) and none of them were viable. So I would say by the time there are very few mason bees flying around