DLI will help us turn this instantaneous measurement into something more useful. This info is useful, but only covers a brief moment in time. Think of PPFD as light intensity hitting the plant right this second. The surface area we’re interested in is the surface of our plants and their leaves.

PPFD is a measurement of how many photons of “plant usable” light are reaching a given surface area every second. (PPFD) Photosynthetic Photon Flux Density Think of PAR as the wavelength range of “plant usable” light. We won’t be talking much about PAR in this article, because it doesn’t actually have anything to do with intensity or duration, but it does impact the quality of light your plants receive. Quality full-spectrum LED lights provide lighting in the full PAR wavelength spectrum. When you hear people talking about “far reds” or “blues”, they’re referring to different PAR wavelengths. This is the wavelength range that plants use for photosynthesis.

Light with a wavelength roughly between 400 to 700 nanometers. (PAR) Photosynthetically Active Radiation Before we get started, there are three terms you should be familiar with. By understanding some simplified concepts you’ll be able to buy and place grow lights in your garden with confidence. Understanding daily light integral (DLI) will help you answer those questions. Want to jump to the Plant DLI Chart or DLI Calculator?

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