Grow lamps
I grow orchids under lights myself, and have found four fluorescent cool
whites to be fine. Grow lights extend the spectrum available, and while
many people swear by them, there's still conflicting data as to whether
they're really 10 times better (which is usually about the cost
differential) than cool whites. What does seem to make a difference is
using the longest tubes you can, for available lights drops off
dramatically at both ends of the tubes. Two foot tubes lose almost half
their length; four foot tubes lose a good foot. Eight footers (if you have
the fixtures) give the best usable light. Avoid putting plants at the
ends, and concentrate them in the middle for best results. good luck!