Abbreviation for Photosynthetic Photon Flux. A measurement of the total amount of photosynthetically active radiation (PAR) emitted by a light source per second. It is measured in micromoles per second (µmol/s) and quantifies how many photons in the 400-700 nanometer range (the range plants use for photosynthesis) are being emitted. Unlike PPFD, which measures the amount of light hitting a specific area, PPF measures the total light output from a grow light.
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In the Wild — Example
PPF tells you the total output of the fixture but PPFD tells you what actually reaches your plants.
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