Well, this has been covered pretty thoroughly in the following thread:
<Damn, can't find it>
M, you participated. Do you remember the thread? I think Ganoderma was trying to figure out the best light frequencies for plant growth, which evolved from a discussion about LED grow lights. I checked the Hydroponics thread and the thread on "we need 1 million more houseplants" (or something similar), with no luck. I do remember some of the discussion was a bit off-topic, so maybe it's buried in an unrelated thread.
