OneHitDone
Well-Known Member
Lights were 18/6@OneHitDone how many hours did you run the lights?
"The formula for calculating DLI is: μmol m-2s-1 (or PPFD) x (3600 x photoperiod) / 1,000,000 = DLI (or moles/m2/day)"
DLI
The total output listed on that lamp is 152 PPFD but doesn't say at what height. Even if you were getting the full 152 on the plants and ran it 24/7 you'd get a DLI of 13.
Butterhead lettuce 14-16
It has been a long time since algebra for me so correct me if I'm wrong
(DLI * 1,000,000) / (3600 * photoperiod) = PPFD ?
So you'd want a minimum of 162.03 PPFD actually reaching the plants if ran 24/7.
Your calcs look correct at a glance but the one thing I have noticed is that published DLI and PPFD #'s that were most likely derived from sun grown plant research do not seem to directly cross over to LED lighting. I have also seen others mention the same experience.
I am not certain the total ppf of a 100W metal halide but am certain that it is less than the QB 65.
I am also certain that the plants did not want either more intensity or longer photo period of the light emitted by the HLG 65. Just look how compact, bonsai'd, and tip burned the LED plants were in comparison to the Metal Halide plants.