Photosynthetic Photon Flux (PPF)

Last Updated: January 28, 2019

Definition - What does Photosynthetic Photon Flux (PPF) mean?

Photosynthetic photon flux, or PPF, is a measure of the amount of photosynthetically active radiation (PAR) is reaching any area for a duration of one second. PPF, or PPFD (photosynthetic photon flux density) is measured in micromoles per square meter per second or µmol/m2/sec. It is a measure of light that is usable for plants in the visible spectrum between 400 nanometers (nm) and 700 nm. This is as opposed to measuring the output of grow lights in lumens, which is a measure of how humans perceive the light and does not necessarily correlate to how plants use it.

MaximumYield explains Photosynthetic Photon Flux (PPF)

Photosynthetic photon flux is a measure that cannabis growers should pay attention to when determining the effectiveness of their grow lights or when deciding on installing a new grow light system. Research has shown that the amount of PPF at the canopy of cannabis crops should not exceed 1800 µmol/m2/sec and is ideally no less than 1500 µmol/m2/sec. This does not mean that the grow light cannot have a greater output than this as some light is lost or scattered between the source and the target. A light meter can be used to help determine the amount of actual light reaching the crop.

This definition was written in the context of Cannabis
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