Full spectrum means the entire spectrum delivered by sun. This also refers to light delivery across the entire visible spectrum of light.
For the purpose of plant growth, the entire range of light provided by the sun is not utilized. Most plants absorb light across the full visible spectrum. Light at 550nm is absorbed less than all other colours (by only about 3%!). This is the reason why most plants appear green to us. Zero light is absorbed above 750nm.
These grow lights delivers a greater quantity of usable photons than products using these “discrete” blue and red LED sources. These discrete LEDs provide output in very specific frequencies, with very narrow bandwidths. As lighting sources become more powerful, especially in LED lighting, the output in these discreet ranges often exceeds the plant’s ability to use these photons, wasting light and power.
Using the same power to deliver photons across a much broader (full) spectrum insures more efficient use of all available light for plant development.
For a detailed description of Full spectrum light click: https://en.wikipedia.org/wiki/Full-spectrum_light
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