Time to move my orchids indoors. I mainly have cattleyas and crosses, Blc, Lc, Scl, Potinara, and a couple miscellaneous types. They have been out all summer and some are blooming and some have buds now which I would hate to lose to a change in weather/light. I have only had orchids for a year and last winter I had them inside but without any extra lighting. Needless to say, they survived, but did not thrive.

So I need advice on indoor lighting.

I am fortunate to have an "orchid porch" for my plants. The porch is 4 feet wide and 7 feet long, a glass door to the outside and a glass door to the inside. The ceiling is the roof with a sky-light, exposure is north-west - emphasis on north.

I have about 50 orchids. There are no shelves. The orchids are in pots with pot hangers, with 12 cascades of 4-5 staggered orchids to a hook.

The space between the top leaves of the top plant and the top leaves of the bottom plant is from 18 to 36 inches but most of the pots can be re-arranged so this would be 18-24 inches. I know that some of the light would be blocked to the lower orchids, but the hanging arrangement works best for my situation.

I would need lights that would be strong enough for the bottom pots to get enough light. I don't think fluorescent lights would work because the middle/bottom orchids would not be close enough to the bulbs to benefit.

I do not understand any of the nomenclature/specifications/types of bulbs available but in searching various sites suggested in other posts, I found a dual bulb at

http://www.littlegreenhouse.com/accessory/lights4.shtml

This is the "PlantMax Dual Arc Bulb - HPS + MH 1000 Watt"

"600w HPS & 400w MH In One Bulb - The PlantMax Dual Arc Bulb incorporates the best of HPS and MH in one bulb with two simultaneously operating arc tubes that are optimized for peak performance. The 1000 Watt Dual Arc Tube Lamp runs a 400w Metal Halide and 600w HPS in one bulb providing full spectrum lighting for your plants. This PlantMax grow bulb runs on a 1000w HPS ballast and emits 110,000 Lumens."

This bulb would seem to supply the necessary spectrums as well as be strong enough to reach the bottom orchids.

So, three questions to begin with:

1. Is this dual bulb the best choice for my growing conditions?

2. Would one ballast/bulb be sufficient?

3. Information provided indicates that medium wattage HID light should be 4 feet from the top of the plant which would mean the bottom plant could be six feet from the light - is this too far?

I am anxious to get some lights going especially since fall is here and I do not want to be moving the orchids in and out of the porch just to catch a couple hours of light. But I want to have the most effective arrangement for my situation since I am now hooked on orchids! Any advice/suggestions would be appreciated.