1. Deep or "royal Blue" 440-450nm:
I started Rootone-treated 6" cuttings from a "Turgey Fig" under
an array of 18 royal blue Rebel LEDs with about 12W of DC input power. In under two weeks I had a small pot full of roots
and many new leaves starting. Other young cuttings seem to do very well under intense, pure, or at least primarily Royal
Blue light.
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2. Green 520-530nm:
I The peppers produced were, indeed very compact. In fact SO compact that the plants
hardly had room for the peppers they are producing, with overcrowding around the central stem. I later find out there may
be another explanation. See Far Red note.
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3. Far Red 730-740nm:
So my assumption that the elongation of plants growing in shade was due to an increase in the green spectrum appears
wrong. A report in Science Daily from 6/22/11 cites work in Japan (and published in HortTechnology) wherein it is proved that
the effect (at least on cucumber seedlings) is due to a reduction in the far-red light, in respect to red (which they do not
define the wavelength of), filtered out by the taller vegetation. It was discovered through the use of fluorescent lighting
which is devoid of far-red light. Reduced FR causes higher chlorophyll content and thicker leaves, and in some cases less
attractiveness to some insects!
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4. Blue 470nm:
Science Daily (12/12/11) Blue light on seedlings (lettuce) increases stem and leaf mass while increasing phenolic
compounds (is this good?). Taken from a study published in HortScience, a Japanese study showed increase in chlorophyll a/b
ratio and carotenoid contents both increased under high blue level conditions.
