What do plant grow lights PAR, PPF, PPFD mean?

If you are not a professional optical engineer or plant expert, when you are new to plant lighting, you are likely to be confused by various technical terms. Let’s learn about these technical terms today.

PAR: Photosynthetically active radiation

     PAR is the acronym of photosynthetic active radiation, which refers to the wavelength of 400~700nm used by plants for photosynthesis. There are two labeling units, one is expressed by photosynthetic irradiance (w/m2), which is mainly used for the generalized study of photosynthesis of sunlight, and the other is expressed by photosynthetic photon flux density PPFD, which is mainly used for the study of plant photosynthesis by artificial light sources, that is, plant grow lights.

PPF: Photophoton traffic

PPF is the acronym of photosynthetic photon flux English word Photosynthetic Photon Flux, the unit is umol/s, indicating how many photosynthetic photons a plant grow light can emit in a second, when designing and formulating the spectral morphology of plant lights, PPF has been determined, and its value is measured with an integrating sphere.

PPFD: Photophoton traffic density

PPFD is an important indicator to measure the performance of grow lights, and is an acronym for photosynthetic photon flux density. The unit is umol/m2/s, which represents PPF within one square meter, PPFD measures the number of photons that fall on plants, and PPFD can be tested or simulated by tester or software. In addition to the influence of its own lamps, the height and surface reflectivity of plants and lamps will also affect the PPFD value, which is inversely proportional to the square of the irradiation distance.

Post time: Oct-24-2022