This is a great article, but I think you mixed up PPF and PPFD. PPF is the acronym for Photosynthetic Photon Flux, measured in umol/s, it is the measurement of how much total PAR light a fixture can produce. PPFD is the acronym of Photosynthetic Photon Flux Density, measured in umol/m2/s. It represents the PPF within one square meter, which is the number of PAR photons falling on a given surface per second.
PPFD is always less than total PPF, right?
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