I forgot to mention that this is a commercial setup. There are five levels of shelving from floor to ceiling and hundreds of flasks. The walls are painted white to increase indirect light reflection.

what's the temp like? i don't know much, but i do know that seedlings are definitely more fussy with low temps than larger plants. also, 18 inches is kinda too high. are they t12's or t8's? overdriven? i use t8's, normal and overdriven. depending on which orchids you have, i would at least lower those fl lights to under a foot from the top of the leaves of the seedlings, and that would be pretty close to the level of the agar for flasked seedlings. for phalaenopsis, try to keep the light readings to between 800-1500 fc. for catt's and onc's keep the fc higher, probably about 1500-2000fc. i might even recommend more intense lighting--mh, etc.

by the way, your questions will probably get more responses in the orchid forum.

Edward

I agree. I think you could get a recommendation here on which lamps to use to get a particular type of light, but I for one don't know anything about raising Orchids :)