Vanda under CF?

[Daemos]

Sorry to ask guys. I have read the entire light forum but can't make up my mind about this little thing.

My window is facing northeast so the amount of sunlight is way too low to get a vanda to bloom. So Ill try artificial light like Ross adviced.
I ordered a CFL growlamp 120W 6500K with 80+ CRI. If I leave the plant hanging in the small window and put this lamp right next to it, will I get away with it
In principle I have some natural light and even some more when the weather si fine.

Anyone having experience with specificly vanda in combo with CFL growlight?

[Ross]

Couple thgings to think about. Keep in mind I don't grow Vandas and know nothing about them. I measure approx 2000 foot candles about 4" (10cm) from my 105 watt bulb, so you might expect 2500 at same distance. Also you will be feeding that much light constant over the length of time you select for the "on cycle". Outdoors or in nature this would not be true as light would start out dim in morning, increasing to mid afternoon and then dimming down by dusk. So total light energy may be pretty high even at 2000-2500 foot candles.

[Daemos]

Ok lets see if I get this footcandle story right. If I expect 2500 footcandles at 10 cm that would be something like 27000 lux. Normal daylight (min.) is something about 30000 lux according to wiki. I have no clue how much sunlight is coming through my window but lets say we are talking about roughly 3700 footcandles if I combine CFL with daylight on mid day. Am I right about this??

[Daemos]

Ah i found it.

This is a citation from a google search on footcandles:

Phalaenopsis 1000-1500 fc Never exposed to direct sun light.
Paphiopedilums 1000-3000 fc Expose to only early morning sun.
Miltonia 1000-3000 fc Keep in diffused light.
Odontoglossums 1500-2000 fc Expose only to morning or evening sun.
Cattleyas 1500-3500 fc Give plenty of light without burning their leaves.
Vanda 1500-4000 fc They like strong light, full morning sun.
Oncidiums 1500-4000 fc Same as above.
Dendrobiums 1500-4000 fc Same as above.
Cymbidiums 7000-8000 fc Give as much light as possible without burning the leaves. Provide lower light (2000-3000 fc) when flower spike appears.

vandas need between 1500 and 4000 footcandles. Lucky for me I don't own Cymbidiums they need even more!! Ill propably get away with it if I have to believe this. Offcourse a personal experience is still welcome. Thnx for the quick reply.

[Ross]

One thing I forgot to mention: the light near that bulb will be so strong you will want to slowly move your vanda near it. Start with maybe 30cm and ever week move it like 5cm or so closer. Watch the leaves. They should be light green, not dark green - at least that's the way it is with other orchids. That light should be strong enough to move the vanda away from the window if you care to.

[Daemos]

Cool thanks a lot for the tip.

I measured my candlelights at the window the poor plant is hanging today and I thought why not share the results. When the sky is cloudy and all covered I measure about 500 cf. When the morning sun is blasting through the window about 1500 cf and after 12 its about 800-1000 cf. Thes results are very non scientific since I used a manual camera to do this. Since vanda's need at least 2500 cf a day I must use at least one 100W lamp to get it blooming.

now comes my follow up question concerning these measurements (Im not getting annoying am I?). Can I simply state that if a lamp gives 2500 cf and the daylight 1000 cf. I can safely say 2500+1000 = 3500 cf or doesn't it work that way?

[Ross]

No, I don't think it's collective. I think there would be some increase but not like that (I'm not certain of this however). I do believe you'll get sufficient light from the 120 watt near the window. My 105 plus 2 55 watt bulbs hang in a south window and I have a window screen over the glass which holds down some of the direct sun. I have Phals and Paphs under that lighting and they do marvelous.

[Daemos]

Super! All I have to do now is wait till all the equipment has arrived and wait patiently for the nature to do the rest.

[Daemos]

OMG that lamp is NUTS. If I have to believe my camera it shoots out something like 3500 fc 20 cm away. It lites the room as if the sun is shining head on to the window.
It was all worth the if you ask me. Lets see what is going to happen.

Starting from 30cm distance seems like a more then wise plan with this punisher lamp.

now for another question. do you guys meassure fc facing the sensor into the lightsource or facing away from it?? In my situation. Do I have to face the camera lens into the lightbulb or into the plant surface when measuring correct fc??

[Ross]

Depends on the light meter. A camera light meter measures refected light since the photog is mostly interested in how bright the subject is, not the light source. An incidence meter (has a white dome on it) is meant to point towatd the light source from the subject location. So if you use your camera, you would point it at a white card sitting where the plant will be. I use a dedicated lux/foot-candle meter and point it at the light source while it sits at the plant's location. Does this help?