Well ,seems to me some folks ,have trouble " digesting " / grasping some stuff ... .....
1)
McCree 1972.
Relative quantum Efficiency .
"Blue broad band 400-499 nm " : Highest RQE of the band is at
424 nm - 434 nm ,
with a value of
0.76 ( 450 nm has RQE of 0.75 )
"Green band 500-550 nm " : Highest RQE of the band is at
550 nm (can't get any greener than that ! ) ,
with a value of
0.87
"Yellow-Amber band 551-600 nm " : Highest RQE of the band is at
596-600 nm ,
with a value of
1
"Red broadband 601-700 nm " : Highest RQE of the band is at
601-627 nm ,
with a value of
1 ( 640 nm RQE= 0,96 , 660 nm RQE = 0,93 )
https://en.wikipedia.org/wiki/Quantum_yield
http://www.life.illinois.edu/govindjee/photosynBook/Chapter11.pdf
2)
Absorptance
Cannabis L. Sativa Absorptance ( 5 July ,Colombian Landstrain )
450 nm ,Blue absorptance : 0.93
550 nm ,Green absorptance :0.75
600nm ,Amber absorptance :0.86
625 ,Red absorptance :0.89
640 ,Red absorptance :0.9
660 ,Red absorptance : 0.93
http://hydrolab.arsusda.gov/Daughtry/Reprints/Spectral Discrim Cannabis 1998.pdf
https://www.rollitup.org/t/what-kind-of-light-mj-likes-decoded-from-its-reflectance.658111/
https://www.rollitup.org/t/photosynthesis-under-solid-state-light-setting-the-standards.833449/
So ....
- Cannabis plant species need 8-10 photons to fix one molecule of CO2 .
Let us assume this scenario :
6 different monochromatic light sources are used to radiate a Cannabis plant .
1x 450 nm ,1x 550 nm , 1x600 nm ,1x 625 nm ,1x 640 nm & lastly 1x 660 nm ..
Let us assume that all 6 light sources emit the same photon flux.
Say
100 photons per sec .
Let us see how much CO2 is being used ,in each case ...
450 nm : From 100 photons per sec ,the 93% is absorbed ,thus 93 photons .
From those 93 photons ,75% are utilised for CO2 fixation .Thus
93* 0.75 = 69.75 = ~ 70 ,thus
7 molecules/sec of CO2 are fixed ,at 450 nm .
550 nm : 100 * 0.75 * 0.87= ~ 65 =
6.5 molecules/sec of CO2 are fixed ,at 550 nm.
600 nm :100 * 0.86 * 1 = 86 =
8.6 molecules/sec of CO2 are fixed ,at 600 nm.
625 nm :100 * 0.89 * 1 = 89 =
8.9 molecules/sec of CO2 are fixed ,at 625 nm
640 nm : 100 * 0.9 * 0.96 = ~86 =
8.6 molecules/sec of CO2 are fixed ,at 640 nm.
660 nm : 100 *0.93 * 0.93 = ~86 =
8.6 molecules/sec of CO2 are fixed ,at 660 nm.
And all that happens at the top layer canopy ....
Now imagine what happens at the lower levels of leaf canopy ....
With available only the 7% of the initial 450 nm & 660 nm quanta ....
......
Saved by the remaining 25% of the initial green quanta .....
" Green window " of vigor and health .....
Green light drives photosynthesis ,almost as good as blue light ,at top layer leaf canopies ...
At lower/ deeper leaves ....Green light-almost "only" - drives photosynthesis .
Way better than blue or red ...
Cheers.
) ,that if a grower hangs that in a grow tent or room ,
