What are your thoughts on this analysis:
Photosynthetic response of Cannabis sativa L. to variations in photosynthetic photon flux densities, temperature and CO2 conditions:
http://home.olemiss.edu/~suman/PhysiologyandMol.Biol.2008.pdf
Among other things it states:
"...the maximum rate of photosynthesis
(PN max) was observed at 30 oC and under 1500 µmol m-2s-1 PPFD."
Optimal lumen/sq. ft. (after converting µmol to lux to lumen) is 11,427 lumen/square foot
400w CMH is 38,400 lumen/sq. ft @ 1 ft.
400w CMH is 17,100 lumen/sq. ft @ 1.5 ft.
400w CMH is 12,500 lumen/sq. ft @ 1.75 ft. (most plants are around this distance.)
400w CMH is 11,700 lumen/sq. ft @ 1.80 ft. (Here's as close to optimal as it gets. Many plants are here.)
400w CMH is 10,400 lumen/sq. ft @ 1.92 sq. ft (distance to the back side of the corner plants.)
Thoughts?