Brassovola nodosa buds are blasting
 

I moved away from my greenhouse last fall and have been growing orchids in a south window with a double sheer shade. The plants are on trays with stones one inch deep. The stones are kept wet. Most of the plants are doing well but the brassovola nodosa has not set many buds and the ones that developed have blasted before opening. It is on bark which I have set above the stone filled tray. This plant is at least 15 years old and was a prolific bloomer until this winter. Should I somehow take it off the bark and plant it in a pot? Has anyone had success growing this in a wondow?
Thanks for any help.