Orchidarium lighting
 

Hello,

I am on the brink of putting the final touches on my brand new orchidarium and was wondering about the light strength:

So far, my lamps produce 40k Lumen (8 T5 tubes ), with a ground floor surface of 12.5 feet ( 30 inch high ).
Assuming no losses, this comes to about 3.5k Foot/candles according to my calculations.

I cannot measure accurately how much are they really getting.
Would you think I will be frying my lower light plants with such intensities?

Will it have a Grail beacon?

Not sure I know what you mean by that.

It's a reference to Monty Python and the Holy Grail, a movie released in the US in 1974. Your avatar is King Arthur and his squire. In the movie they were on foot, but pretending to be mounted. The squire clicked together two coconut shells in imitation of clopping horse hooves. Just like your avatar.

In one scene Sir Launcelot thought he saw an image of the Holy Grail shining above Castle Anthrax. But it was just the grail-shaped beacon that Dingo realized her naughty twin sister Zoot had lighted. She begged Launcelot to spank her and the three score blondes, brunettes and redheads in the castle, all between the ages of 18 and 22, as punishment. Fortunately Launcelot was rescued by another knight just as he was about to give in.

I thought based on your avatar that you would catch the reference.

Crap.
That I figured but could not believe it :)
This would the first time somebody figured it out.

Personally, I think your going to bake everything in there, unless the light fixture is elevated quite a bit over the tank.

You're talking 8 - 4', 54w bulbs, right? Over an enclosure roughly 4' x 3' x 3' tall, I would speculate that 4 bulbs is plenty, even for the brightest-growing plants.

Yes.
The box is 60x30x30. The light is maybe 2" above this.
I had a hunch it might be a bit strong.

I roughly follwed the design from this guy, which suggested 8 tubes for a box slightly smaller:
Orchids in Bloom: My Orchidarium

This is not just ANY orchid forum.

Look at the dates on this blog posts! They were late in the 1980's, suggesting that - at best - his 48" bulbs were 40-watters, putting out about 40 lumens/watt, so his maximum output was 8 x 40 x 40 = 12,800 lumens. Three T5HO bulbs at 54W and 90 lumens/watt will put out more light than that!

I can always use just 4 lights.
8 lights felt a bit much, but ohh well. I guess I did not think of that :)