Lighting My Orchid Cave

[Gareth]

What formula do I use for how many grow lights and what kind I need for a 7' long x 6' high x 5' deep growing chamber i.e. (orchidarium)?

My plan is to have this chamber for orchids demanding more light. I want to use big lights, or as big as would be required. The chamber will house as many orchids as practical using shelving. Low light orchids will be in a different grow chamber.

Thanks for helping me design what I call my orchid cave.

[neb]

I am no expert but from what I have seen some where around 60/40 or 70/30 metal halide to high pressure sodium lights is good to get flower growth and have ok color rendering. And to cover that space it may take 1200 watts spread out with 4 bulbs. But I have just seen a few setups. I hope someone with more expertise will chime in.

[Ray]

I could be wrong about this, but I think that in an enclosed chamber, MH or HPS lights may generate way too much heat. I think high-output T5 fluorescents would be the way to go.

For a 7' x 5' growing area, you could put up as many as three 4' x 8 tube fixtures.

Don't forget that no matter what light source you use, the inverse-square intensity drop-off still applies, so you'll have some differences in light levels over that 6-foot height.