I recently was struggling with the same question and ended up buying a HID
250W HPS (~$200.00 at Hydroponic Discounters) ballast with a SuperAgro
bulb for extra blue spectrum. It is my only source of light and it seems
to be working fine. Since then, however, I've discovered Wonderlite 150W
bulbs for $49.00 each that screw into a $10 ceramic socket from Home
Depot. At three feet above the orchids they create a 5 foot diameter
growing area at about 3000 foot candles, seemingly bright enough to grow
most plants. I'm not sure if it is as good or maybe better than the HPS
unit, but sure a lot less expensive and more attractive. I wonder what
others think?

Charles

wrote:

I'd like to add growing lights to my orchid room to encourage Phals and
Mini Cats to bloom. I have about 30 plants in 4" to 5" pots. (The
dendrobiums seem to do fine without it.)

I'm looking at a catalogue from Charlie's Greenhouse, and I'm confused
about what to buy. I'm not sure whether I need fluorescent lights with
two adjacent tubes or four adjacent tubes--or if four are better than
two. They also have HID lights, but they come in all sorts of
intensities. Which is best for indoors for a small area? For about
$500, can I buy lights that will make a difference in my orchids'
flowering?

Thanks for any input that you can provide.