For growing plants indoors with LED light fixtures we have to take both Watts & PPFD.... Why?
Because everyone remembers light bulbs & their power or brightness was indicated in Watts I'm speaking in layman terms.LEDs have replaced the light bulbs so everybody is familiar with those terms. Now throw in PPFD. Now we are speaking "Horticulture". Which is a science within itself.
So combine the two.
Now you have PPFD/W(Per Watt)
Photosynthetic Photon Flux or PPF measures the “photosynthetically active photons emitted by a
lighting system per second”. The key word is "synthetic" because it is artificial & not derived from the Sun) This measurement is expressed in μmol/s (A Metric). This metric is the “equivalent” of
Lumens for plants.
Photon Efficacy or PPF/W refers to how efficient a horticulture lighting system is at converting
electrical energy into photons.
This measurement is expressed in μmol/J.
Photosynthetic Photon Flux Density or PPFD is a measurement
(metric) of the number of photosynthetically active photons that fall on a given surface each second.
It is expressed in μmol/m2 /s.
Day Light Integral or DLI is a cumulative measurement of the total number of photons that reach a given surface during the daily photoperiod.
DLI is expressed in mol/m2/d.
Now, all of this must be considered to do it properly & have an in-depth understanding of what you're trying to grow. That is why I asked "what are you growing???"
LED-based fixtures are being introduced with PPF/W values close to 3.0 mmol/J (for comparison the best HPS
(You have to be some work look up HPS) lamps are at 1.7 mmol/J).
It's all about wavelength or photosynthetic wavelength. Which is oxymoron.



