For decades now, growers have been obsessed with the lumen output of their
lamps, misguidedly thinking that the more lumens, then the better the light is for
the plant. Lumens is how we started to measure light back in the day and is a
measurement by its availability to the human eye curve and is the industry standard
way of measuring any lamp.
Plants do not even recognize what a lumen is, but instead rely on photons hitting
the surface of the leaf to make them grow, these photons we call PAR
(photosynthetic active radiation). PAR is measured in micromoles (μmol m
-2
s
-1
) and
is basically the number of photons hitting a surface that are available for use by the
plant.
PAR VALUE(µmol m-2 s-1)
2598
1226
688
473
347
0”
8”
16”
24”
32”
40”
1860
888
483
332
242
0”
8”
16”
24”
32”
40”
VEG
BLOOM
5
