There is probably a way - just will take some good preparation. Maybe if you had "X" amount of rocks in the bottom you could count on the media draining sufficiently into the rock layer? Another concept to try might be semi-hydro - often written as "S/H". I have not tried it myself, but some growers grow all of their orchids in this media/technique. Here is a link you might check out -
http://www.firstrays.com/hydro.htm You might also email them and see what type of orchid they would suggest for your environment? Good luck. mike