Is My Light Right? or too Bright? ... like a Kite?

[Undergrounder]

I went to a hydro store today to supplement my light setup and i told the guy i was growing orchids and i said the orchids i want to grow are low-light Phalaenopsis/Paphiopedilum and i mentioned i'd heard that cool fluorescent grow lights are reccommended, etc. etc. etc.

The guy hands me this thing:



and assures me this is what i want. He says its good for flowering. 'I don't need it to be bright' i say. 'That light looks a bit too red' i say. 'What about these (standard fluoros) i say'

'No no no' he says, 'i assure you this is the one you want ... Its great for flowering' he repeats. (There's nothing on the box to hint on its spectrum or intensity other than 100W).

So i give in and say i'll give it a go, i come home, google some words form the packaging and find out its mainly 2700 reddish spectrum (i knew it looked red) and boy its pretty bright.



Will this do? Ill keep it if you say its OK but i do remember reading that much broader spectrums up to and around 5000k are reccommended.

Im wanting it mainly for Phals, Paphs, Dendrochilum, Sarcochilus, all low-light genera.

I think maybe he thought i was growing weed and just using the orchid thing as 'code' or something and gave me this red, bright, flowering bulb no matter what i said. I wonder how much of their business are kids growing 'canna... err tomatoes' in their cupboards.

[Ross]

For all around use with most plants, and orchids in particular, you want 5000K lamps or close to that. 6500K are OK but maybe a mix is better. The reason for 500K is that is the color temperature of the sun (full sunlight - no clouds) at noon at the equator. Your sun may register a bit higher K as you are further from the equator.

[Ray]

I agree with Ross - take it back and get the one closest to a 5000°K color temperature, as it will likely have similar out put levels at the spectral regions surrounding those needed by the plant - 425 to 450 nm and 650-675 nm.

If I remember correctly, the red end of the spectrum primarily affects vegetative growth, and the blue end favors blooming (somebody better check me on that before accepting it), which is why incandescent "grow lights" often have a blue coating and fluorescent ones have a pinker phosphor than does "cool white".

For the all-around best environment, a balance of the two is the target.

[FinnBar]

yes, get something within the 5000-6500K range.

hydroponics guys always say the 2700K is good for blooming. my theory on is that switching from a 6000 or so Ks and a bluish spectrum into the 2700K plants believe it's autumn because the change of spectrum puts out more red and (for the plants useless) yellow which causes a drop on the actual light levels.

i seriously doubt they would work when used constantly in hydroponics and i believe that applies to orchids too.

[dupree1977]

"Oh, 'orchids' huh?" <wink> I'd wager it happens a lot with lighting stores.

The joke in my family since I started growing orchids in the basement is that either the orchids are a cover-up for the weed I'm really growing or that I intend to grow weed on the side to support my orchid habit.

Originally Posted by Undergrounder

I think maybe he thought i was growing weed and just using the orchid thing as 'code' or something and gave me this red, bright, flowering bulb no matter what i said. I wonder how much of their business are kids growing 'canna... err tomatoes' in their cupboards.

[Ross]

Originally Posted by Ray

If I remember correctly, the red end of the spectrum primarily affects vegetative growth, and the blue end favors blooming (somebody better check me on that before accepting it), which is why incandescent "grow lights" often have a blue coating and fluorescent ones have a pinker phosphor than does "cool white".

You are on the right track Ray, but backwards. Red end "supposedly" stimulates flowering and blue end green growth. This is based on the (in my mind) mistaken believe all flowering is due to change or season. Yes, as seasons wane and sun drops lower in horizon (for lots of folks), light gets redder. In spring (corresponding to normal flush of growth) sun is getting higher in sky resulting in bluer light. Easy to attach this to a scenario where red light = blossoms and blue light = growth. All I ask is what about the equator, where relative day length and sun position is the same all year around? I really need to start a new thread, because this is rapidly turning into an article. Think I'll do that and let the readers here ponder and interact with that article.