Spring is notorious for its rainy days and stormy weather amongst some beautiful sunny days.
If you set out all your mason bee cocoons out at one time, bees might catch a bit of sunny weather, pollinate your fruit trees and produce offspring for next year.
But, if bad weather arrives and it stays around for 2 weeks, it is likely you will not get any mason bee offspring nor will you have any pollination.
With a few mason bees, there is no choice but to set out your cocoons at one time. Hopefully the weather is reasonable.
However if you have a handful of bees, maybe 50, 100, 200 etc, you can divide them up into 3 or 4 batches. Set the first group of cocoons out about once week before tree fruit begins to bloom.
Then, make a schedule and write it on a calendar, perhaps setting out the 2nd, 3rd and 4th batch of cocoons out every week.
If the rain does come, it will wipe out one of the batches, but not every batch of mason bee cocoons.
Good luck!
It is all about timing…..