Light Spectra Used
Natural daylight has a high color temperature (approx. 5000 K). Visible light color varies according to the weather, and angle of the Sun, and specific quantities (measured in Lumens) of light stimulate photosynthesis. Distance from the sun has little effect on seasonal changes in the quality and quantity of light and the resulting plant behavior during those seasons. The Earth tilts on its axis as it revolves around the sun. During the summer we get nearly direct sunlight and during the winter we get sunlight at a 23.44 degree angle to the equator. This small tilt of the Earth's axis changes the effective thickness of the atmosphere with respect to the distance sunlight has to travel to reach our particular area on Earth. The color spectrum of light that the sun sends us does not change, only the quantity and quality of overall light reaching us. The color rendering index allows comparison of how closely the light matches the natural color of regular sunlight.
Different stages of plant growth require different spectra. The initial vegetative stage requires blue spectrum of light, whereas the later "flowering" stage is usually done with red–orange spectra.
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Famous quotes containing the word light:
“Separated lovers cheat absence by a thousand fancies which have their own reality. They are prevented from seeing one another and they cannot write; nevertheless they find countless mysterious ways of corresponding, by sending each other the song of birds, the scent of flowers, the laughter of children, the light of the sun, the sighing of the wind, and the gleam of the stars—all the beauties of creation.”
—Victor Hugo (1802–1885)