page_title: Grow light
section_title: Light Quality
hierarchical_section_title: Grow light / Light requirements of plants / Light Quality
caption_attribution_description: English: A panel of red LEDs used for illumination for a plant growth experiment with possible future application to food growing in space. From spuds to space medicine. Quantum Devices Inc., of Barneveld, Wis., builds the light-emitting diodes used in medical devices and for growing plants, like potatoes, inside the ASTROCULTUREŠ facility -- a plant growth unit developed for use on the Space Shuttle by the Wisconsin Center for Space Automation and Robotics (WCSAR). WCSAR is one of 16 NASA Commercial Space Centers that help companies fly experiments in space. The ASTROCULTUREŠ facility has flown on eight Space Shuttle missions, including this one in 1995 in which potatoes were grown in space. The LEDs will be used in the ADVANCED ASTROCULTUREŠ unit next year on the International Space Station. Such commercial payloads are flown under the Space Product Development Program at NASA's Marshall Space Flight Center in Huntsville, Ala. NASA's lead center for microgravity research.
context_page_description: Grow lights either attempt to provide a light spectrum similar to that of the sun, or to provide a spectrum that is more tailored to the needs of the plants being cultivated. Outdoor conditions are mimicked with varying colour, temperatures and spectral outputs from the grow light, as well as varying the intensity of the lamps. Depending on the type of plant being cultivated, the stage of cultivation, and the photoperiod required by the plants, specific ranges of spectrum, luminous efficacy and color temperature are desirable for use with specific plants and time periods.
  Russian botanist Andrei Famintsyn was the first to use artificial light for plant growing and research.
context_section_description: Light quality refers to the spectral distribution of light given to a plant. Light quality is grouped into colors based on wavelength; 320-400 nanometers (nm) is UVA, 400-500 nm is blue, 500-600 nm is green, 600-700 nm is red, and 700-750 nm is far red, sometimes referred to as near-infrared. Light quality can also be expressed as ratios, e.g. 3:2 red:blue ratio, or sometimes as their peak irradiance, e.g. 450 nm blue light and 660 nm red light.
  Photomorphogenesis is the term for light-mediated plant responses to light spectrum. Plants are able to sense parts of the electromagnetic spectrum through a network of photoreceptors including phytochromes, cryptochromes, phototropin, and zeiltupe. Each receptor is able to sense different parts of the electromagnetic spectrum. Information about the light spectrum can affect seed germination, the signal to transition from vegetative to flowering, and the production of secondary metabolites such as anthocyanins.
caption: LED panel light source used in an experiment on potato plant growth by NASA
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