Quote:
Originally Posted by dnatural1
Hi gdupont,
I'd go with your second choice "Twin Pack LED Grow Lights for Indoor Plants" as it's spectrum coincides well with the absorption spectra of chlorophyll a "The absorption peaks of chlorophyll a are at 665 nm and 465 nm" (see https://en.wikipedia.org/wiki/Chlorophyll). |
dnaural1, as Ray has pointed out, you are making a common misunderstanding here (I used to make this wide-spread mistake, too). Chlorophyll absorption is just a part of photosynthetic efficiency.
See the red line in the figure next to yield photon flux section:
https://en.wikipedia.org/wiki/Photos...tive_radiation
This graph shows how different wavelength may influence the photosynthetic efficiency. You can compare it with the chlorophyll absorption spectrum, and you'll notice the difference. One thing I should note is that this photosynthetic action spectrum is measured from full sun crop plants. Orchids might have quite different responses.
At this moment, many of the LED grow light makers are moving toward white + monochromatic (a bit of red) from the old fashioned red/blue + a couple monochromatics. This is mainly due to the rapid improvement in performance/cost of white (compared to mono's). So you'll get higher PAR efficiency for a given emitter cost with high-performance whites.
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