I have grown the majority of my orchids for quite some time under a MH system. I believe it is the best choice for light demanding genera such as Cattleya and Vanda. My grow area is 4 ft wide/5 ft long/ 3ft high. The plants are 12-18 " from the light. I operate a 400W system with an air cooled cylinder reflector. This keeps the bulb cooler and protects it. I also keep the air circulation very high which keeps the heat down and also dries the plant roots quickly. I suppliment with warm (3000K) T5's. The bulb I use is red enhanced, or warmer than a traditional MH lamp. I've developed a method where I cycle the MH light. I have it hooked to a timer which turns on the timer for 2 hour periods with a 2 hour rest between each MH light session. When the MH system is off, the plants are getting the light from the T5's. This really works for me and the plants get lots of light without overheating and burning. Yes, the HID systems give off alot of light and quite a bit of heat. I have also seen people who have used them in shelving systems. My plants flourish under my set-up. Daily temperature is 30-35C/nightly is 20-25C. RH remains at 50-70 %. I grow Vanda, Catts, Beallara, Catasetum, Phals,Paphs, Brassia, etc. Good luck!

Metal halide is great if you can stand the heat. However, if the shelf your plants are on is only 18" deep you will certainly not be taking advantage of the light spread. 1000 watts is quite a bit, perhaps overkill in my opinion given what you've described. Perhaps 600 watts? Hopefully someone a bit more educated on this than I can give some pointers.

I have used MH and HPS in the past but recently found a vender on ebay that sells the T5 fluorescents in a custom configuration that grows my cattleyas just fine. The lights are 4 T5's 4' long and they fit perfectly on the shelving unit which is also 18" wide. Feel free to have a look, his name is dinosore777. If you email him he can give you an expert recommendation as to what would be best in your situation. He sells all types of lighting 1000 watt MH as well. Here's the link.

I hope this helps you out.

Regards,
Erica

Here is a link that might be useful: dinosore777

I agree with Erica. You are probably better going with T5's in your situation. T5's are great but I have found that the plants have to be really close to the lights to obtain the greatest benefit. This is easily achieved in a shelf set-up. -Carlos

Because a thing 'works' or rather appears to work does not always mean it in fact does and IMO the usage of the HID technology outlined above is absolutely contrary to every published method for their use. It is well known that every time you start a lamp you stress the filament and/or electronics and because of this the rated life of all lamps regardless of technology is calculated using a minimum run time of 8 hours per start. Next, the photosynthetic response of plants I have been told works on a 20 minute response cycle. The technicalities of this are beyond me but basically interruptions longer than 20 minutes bring the process back to zero from which it must recommence. MH and HPS lamps are not nearly as hot as is commonly feared. A 500W incandescent 'is' hot and will start fires. A 1000W incandescent does not even exist to my knowledge. A 500W MH can be used within 12" of many orchids and within 24" of all but best would be the employ of a light mover for HID bulbs larger than 500W. The other posters are correct, for a shelf system the only lighting options that make sense are multiple medium wattage CFL or HO or VHO T5 tubes. MH is a point source light and its output is circular. A square growing area that fits within the circle of coverage is the best usage of an HID lamp.

H

Thanks everyone for your input. And Howard, that is exactly the info I was looking for and you saved me hours of internet searching to find it.

I had reservations about attempting to put a MH light on a shelving unit and you confirmed it for me.

Next step - I am looking into T5's.

Thanks again.

I have the 1000W set up from dinosore777 and love it. It is used in an entirely different situation than yours. It is hanging from the ceiling in a roon with South and East sunlight. The reflector is positioned to cover the area of the room in the Southeast corner. What the sun doesn't cover the light does. Probably a 10' x 10' area. The light does produce heat, but adds wonderfully to the temp of the room. I have Phal. and mostly Brazilian Cats. When the light goes out the temp settles down to a comfortable night temp drop. A fan and two humidifiers run all day. Only been doing this for about one month, but all the plants seem to love it.

I am a VERY new collector and learning so much from all these questions and answers. I think by looking at the dinosore777 page that the 6 compact bloom and grow lights would be very good, but I can't hang them from the ceiling; I would need a octopus lamp, I guess, so that they it could sit on the floor. I read in one of these questions that they have them in Target and Lowes. I already tried Home Depot and didn't find any. Would I have to do anything to these lamps to customize them for using with plants, like inserting a ceramic converter or using something to reflect the light better?

Many thanks,

Barb

I have a small table approx. 3 ft square with a Target octopus floor lamp over it. It has 5 light fixtures. I put 100 wt equivalent CFL's in them. 500 wt of CFL's and I am growing 8 Catts under them. I am so impressed with the growth. This is a dark office with no outside light. They have been under this setup since December. I have 3 small Phals on the outer rim of the lights. I also have 2C.Gaskelliana growing very well closer to the lights.

The Target floor lamp cost $18.00 on line with free shipping. I bought 3 of them and have them in various places around my house. I mention this small set-up because it is the only one which is totally dependent on the lights. My other plants get outside light along with the lamps. I have squashed a lot of plants under that small set-up, but they are doing well and I'm pleased with the growth.
Jane

Thank you so much. I already went to Target online and bought one of the octapus floor lamps. Then I went to dinosore777 to look at the lights. There was a set of 6 bloom grow light compact CFLs. I have an email into the seller asking if I have an octopus lamp with 5 arms, which of the 6 lights do I leave off. The set of 6 lights was 3 that had, I believe, the red, and the other 3 that were blue or green - I can't remember which.

You guys are so great!

Barb

erica, thank you so much for the recommendation for dinosore777. I just got a 4 tube high output T5 fixture from him and so far I am very happy with it. I wish I hadn't misplaced my light meter, but it sure is bright. I bought it to replace my cheap shop lights that would keep dying prematurely on me. If this light holds up, I'll be getting another for the other shelf on my rack when the remaining shop lights bite the dust.

BTW, he has a new name now on ebay -

greatlights4less!

(With the exclamation mark in his name.)

Hello,
I have been using HID for several years now, I have been able to grow and Bloom Vandas with little trouble with my light and feeding program. I have a grow room constructed that maintains the warmth and humidity needed for these plants. I use (2) 400 watt MH and a 200 watt HPS I have these set up to run on timers, I start the HPS for 2 hours in the morning and bring the first MH on until mid way into my light cycle. At that point I turn off the HPS and bring in the 2nd MH lamp until the final 2 hours of the lighting cycle in which I run only 1 MH. My lighting cycle dependent on the season are from12 to 18 hours.

My Cats love the light, If you have Paphs I just move them to the edges of the light bed. Hope this helps