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Re: [APD] Green HPS bulbs? No thanks.
David A. Youngker wrote:
> I love these discussions - it's like listening to audiophiles in the '60s
> and '70s talking the specs on their stereos. So many people willing to pay
> extra hundreds of dollars to gain an added 0.001% response from their
> equipment when they left their _ears_ behind long ago...
>I calculate the numbers because 1) it was fun making the
>calculator 2) to get a rather fair comparsion between bulbs
>3) to be able to explain to myself why I had massive pearling with
>Aquarelles and not SunGlo (recommended by Tropica) and
>not GroLux and not Biolux.
I didn't use my ears, but my eyes. HPS = Sunglo in this example.
> Daniel - looking at the chart you reference, the area under both the blue
> AND green spectral curves _combined_ don't even equal the area represented
> by the red alone, much less the yellow. Just "eyeballing" the chart tells
> that a good 70-75% of the illumination produced by the lamp lies above
> 570 nm or so, yet you persist in calling these "green" lamps because of
> single spike that has captured your attention so thoroughly. Get out from
> behind that tree and look at the forest - even a single Redwood isn't as
> impressive as a whole expanse of them.
Yes I will get out behind the tree, actually I already have and calculated
them. They're so-so. Nod bad, certainly not good.
This together with my eyes have convinced me long ago
HPS:es are economically very bad. More blue is also better because
it holds it's energy further down. Not that applicable to our
heights perhaps but still. Stomata opens more under blue light,
so what you wrote on the Google-groups is not applicable.
You also think the phototropic response is due to the 440 nm
length which is not true:
But your're right when you, and T. Barr says
"A plant will grow no matter what the spectrum if the
light is intense enough."
So true, but not if you want to really maximize growth
to the energy you put in. I don't think NASA will use
HPS:es when they will grow plants as fast as they can:
This is not interesting for those that doesn't care when
the electricity bill comes, they use HPS:ses or whatever
crappy light they like the looks of and shoot as hard as
they can. Brute force.
Yellow HPS-light are ugly so the discussion is not
intersting anyway like T. Barr said.
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