I am no expert and others may have a different take on bedding but here is what I think for what its worth (probably not much :D). March and April here in this part of Florida usually best for bedding but.....that is not written in stone. Where you live may be drastically different. It is already May here and most of the beds that I have seen are now empty. As far as conditions, my best guess for bedding would be when the water temp. is warmer like in the 70s or 80s. Just before the full moon couldn't hurt . Beds are usually more shallow depending on the species of bream. I think Shellcrackers like their beds a little deeper than say Bluegill. I don't know about other bream species bedding preferences like warmouth, stumpknockers, fliers, and so on.