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First, my apologies for so often forgetting to change the subject line.  I
have tried to get Eudora to filter my outgoing mail and refuse to send
something with DIGEST in the subject line, but what it does is first send
it, then tell me I shouldn't have.   Shoot!

Second, I have been thinking about lighting.   It seems to me it boils down
to these three TOUGH questions:

1.   What is the photosynthetically active spectrum for our plants
(possibly even different for each plant, but I think that unlikely)?

2.  Which bulbs provide this for the minimum watts consumed or heat
produced or whatever thing you want to think of as bad?

3.  Once we have the light to our plants, how do we resolve any remaining
conflict between what our plants want to grow and what we want so the
plants look nice?

To start on these questions:  The commercially available PAR meters treat
equally all photons between 400-700 nm.  Actually, the one curve I saw went
from about 440-720, but the definition (written) says 400-700nm.  

Now how do we know that corresponds to the needs of our plants?  

And thinking of question 3, what combination of phosphors would make the
plants look best (assuming we go with some variety of FL)?  

In terms of question 2, this would imply a linear map between total
visible radiation and photosynthetic effectiveness.  How do we back out the
bias towards green in lumen figures?

I am confused.  Who can shed some light on this?

Dave Gomberg, San Francisco            mailto:gomberg at wcf_com