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What is PPFD (Photosynthetic Photon Flux Density)?

  PPFD is the most useful measurement for understanding how much usable light plants receive under the glow of a specific lamp. This is because PPFD, or photosynthetic photon flux density, defines the amount of PAR that actually reaches the canopy. This measurement is expressed in micromoles (umol) per meter per second.

How to Choose the Right PPFD Measurements for Your Plants

  There is no one ideal metric for PPFD. The needs of your plants depend on two major factors: the species of your crop and the size of your grow operation. Light intensity continually diminishes the farther you get from the light source. When your grow light manufacturer lists the PPFD specifications for your grow light, be sure to find out what the recommended hanging height and footprint is for that light. A light designed for a personal grow tent won’t have the same impact in a warehouse with 20-foot ceilings.