Icemud420
Well-Known Member
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Ok I think this would be a great lesson for people to learn some things.
A number of you have referenced the Chandra study, which is a very excellent paper, as the basis for the >1000ppfd being beneficial claims. I will first point out that when referencing a document you should read it in its entirety and understand it beforehand. It is very key to know how it may, or in this case may not, support your position.
Kudos to the first person who identifies what element makes this study somewhat invalid for this purpose. Hint: it is in the Material and Methods section.
There are actually a few flaws, but none the less, its the only cannabis specific study with light intensity I have come across.
Flaws:
Only 1 type of cannabis species was tested (mexican variety)
Only red/blue light was used in the test, of specific wavelength, not full spectrum
The leaf samples were only given about 45 minutes of light, where photosynthesis peaks usually right before mid day sun.
The readings of PPFD were only on upper leaves using a closed device/system for measuring photosynthesis, but didn't take into consideration intra canopy measurements, or intensities within the intracanopy.
PPFD results were only measured within the range of 660-675nm. (not even the peak wavelengths for absorption)
Those are the flaws I found upon just quickly re-reading the study... so yes, there are quite a few flaws, but also we have to consider that there are very little light research studies done on cannabis in general, so the data that is gathered from this is useful, to some extent.
and after seeing your second hint, yea, they didn't use Far Red to create the emerson effect which would have influenced the results.
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