In article lobal.net,
Eric wrote:
On Tue, 7 Feb 2006 19:53:09 -0600, Richard Sexton wrote
(in article ):

I don't know of any good reason to. Plants don't care about light color,
people do. Do whatever you think looks good.


I always thought plants did care about light color. For instance, plants
don't absorb much green light (that's why they look green) so shining a lot
of green light on them is useless.

Turns out not.

I spent years trying to find the optimal light color tamperatures
and wavelengths and thought I'd found the answer in the
Kent State Press book "Lighting for plant growth" which
was a) the result of a PhD thesis and b) when and where
gro lux tubs were invented. (Ironically GE supplied them
with tubes they specified, then they sold the thing to
Sylvania).

But, trying years later to back this up I found that that
work was not given much credence, and in more than one
place where scientists were taking measurements on plant
growth I kept seeing the phrase "we found warm white to work
the best of any tube we tried (shrug)" and I've used warm
white ever since. I've tried almost every tube known
and they do seem to be right. People care about light color,
plants don't.

There are minor diferences, red gives slightly more elongated
growth white bluye gives more bush growth, but it's difficult
to notice much of a difference IME.

I thought I could manipulate the color of plants by light
color, but no, it's light intensity that does that it seems.

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