Orchids sitting on moist sphag? Good idea?

[Maree]

I recently bought a Brassia, Zygo and Massi. They all seem to dry out within a day or two. They are in what looks like bark, perlite and charcoal. I hate to transplant since they are all in bloom. Would it be a mistake to sit their pots on a bed of damp sphag to help them retain moisture for longer than a day or two? I made some sphag moist and put it between the plastic pots and decorative pots they sit in. I would love to get them on a 7-10 days watering schedule with my catts and phals. Any info appreciated.