Confusion about Light Intensity with 125W CPF

[bosco]

The readings with a digital light meter correspond to the cheaper meter I've been using

At the suface of the bulb 9600-10000 ft candles

6" distance 2300 ftcandles
12" 1200
18" 550
24" 375
36" 220

These readings where done at night, but the orchidarium does sit close to a large east facing window. However the window faces another building ~20 ft away, so there very little direct sunlight. I've thought about moving the orchidarium to a south and east facing corner window but I think 4hrs of direct sunlight will just destroy my orchids. Before the orchidarium was built I housed a few phals in a terrarium w/o any supplemental lighting, and was placed at the same spot that the orchidarium now sits. These phals are all in spike or flowering, so I think whatever ambient light enters in through this east facing window is sufficient for the phals. I guess I'll just be patient and see what my babies say.

Thanks all for the suggestions and tips, I'll post another thread about the building of my current orchidarium when I have more time.

Sorry I can't PM jrod, I'm a newbie

Nothing but love

Bosco

[IdahoOrchid]

Sorry I can't PM jrod, I'm a newbie

Bosco

So get on the stick and post two more times. Or is it 7 more times. Anyway, it is REALLY easy to get to the post requirement.

Welcome, by the way. I am looking forward to your construction post. Hope I don't miss it. Once you put it up, place a link here!!!

[smartie2000]

I will say aaaah to the 6 inch top portion has too much light! Maybe grow vandas up there I guess, but I don't have experience with those. And Dendrobriums (phal type).

You can grow phal in the 3 ft region I think if you have the lights on for 14-16hrs, but the top potion wouldn't need that many hours so its hard. Paph Maudiae are also low light plants.

Just set up a low wattage light for the bottom half....it will be much easier.

[IdahoOrchid]

I will say aaaah to the 6 inch top portion has too much light! Maybe grow vandas up there I guess, but I don't have experience with those. And Dendrobriums (phal type).

Catts would do well up there in the 1 foot to 18 inch region.

How wide is the beam? You should check it on the edges too since the light is weaker in that area. That would probably give you more possible areas to grow.

[bosco]

At 9:30am, the ambient light adds another 150 ftcandles 6" from the window, 100ft candles at 12" and 75ft candles at 24"

The bulb is ~16" long, and I haven't recorded any difference in light intensity at the side of the tank. I've been thinking about ringing the top 6" of the tank with thin aluminum or copper, so I could glue some mylar to the metal and then attach that to the outside of the tank.

Again, thanks for all the replies, this a great site, I'm glad to come across it

Nothing but love

Bosco

[jrod]

Sounds like a light diffusion issue. You could try swapping out your reflector, to get more light on the bottom of the tank, rather than losing a lot of it into the surrounding room. Otherwise, you might be stuck. Good luck.