Not sure if i have the right light for my phalaenopsis orchids.

[naoki]

I measured 65W incandescent flood light bulbs (I took measurement from 3 bulbs and averaged). Unlike yours, mine is GE 65W Miser Flood, not marketed as "plant" bulb, which I'm not sure if it is a marketing gimmick or if it has a different spectrum. Most incandescent bulbs should have lots of red, which is great for plants. As I speculated earlier, 1x bulb from 8" will be pretty perfect for hybrid Phals (assuming around 13 hours/day).

I include a bit more technical aspects below. Don't read it if you don't care about details (it will probably confuse many people). 8" from 65W incandescent flood light, you get PPFD of 150 micro moles/m^2/s, which is pretty good for artificial light for Phals. You can think PPFD is something similar to foot-candles, but it is more relevant to plants instead of adjusted for human eyes. Full sun is about 2000 micromoles/m^2/s. The bulb consumes 64.5W.

I compared it to CFL flood bulb, and PPFD efficiency isn't much better than incandescent flood, which was a surprise. In other words, you need about 65W of CFL flood to replace 65W of incandescent. Note that I didn't measure the normal spiral kinds of CFL, so this probably won't apply to the normal CFL bulb.

Cree LED is about 4 times more efficient in terms of PPFD than incandescent. I didn't have Cree flood LED, so I used 18W standard A-type bulb with a cheap clip-reflector. This 18W LED gives about 10% more PAR than the 65W incandescent flood bulb. 18W Cree LED is sold as 100W replacement, but they are talking in terms of lumen (green-emphasized measurement). For plant relevant measurement, it replaces 65W incandescent.

[Newbee]

Wow, such great information!! Thank you I will get the new bulbs "ask for them as a christmas present" I could prob lower the lights closer to the orchids with the bulbs i have now but they do put off heat and i was afraid it would burn them. :/

[naoki]

Sounds good, just a bit of clarification. Most people aren't familiar with PPFD, and it may not be easy to interpret (because most books talk in foot candles, which isn't so useful for artificial lighting). But the punch line is that 8" is probably near perfect for your hybrid Phal, so you don't need to make it closer. You could even give a bit more distance if you can feel the heat at the leaf level.

Details: Phalaenopsis researchers seem to use about 10-20% of sunlight for greenhouse. This corresponds to 200-400 micro moles/m^2/s at the noon time. But unlike natural light, artificial light can give continuous light for the entire day, so you can get the similar cumulative amount of light with 150 micro moles/m^2/s.

[Newbee]

Thank you so much for the awsome information, i did go out this evening and bought some new bulbs you suggested for my lamps. Can't wait to put them in tomarrow since my old ones get hot when they are on. Feeling excited Thanks again!

[gngrhill]

First Rays also has a nice compact LED bulb that you might want to try. I got one of those and have 4 small oncidiums under it, about 2 or 3 inches above.