Article Abstracts | March 2008
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Light Management for Controlled-Environment Agriculture
Cornell’s greenhouse project delivers tons of hydroponic lettuce grown under a computerized lighting system.
by Dr. Louis D. Albright, Cornell University
Imagine harvesting crops in New York state in the dead of winter. At Cornell University, a hydroponic greenhouse project is making that happen. In the controlled environment, it takes 35 days to grow one head of hydroponic lettuce, yielding a potential harvest of 390 tons an acre per year. That’s a lot more than the 45 tons of in-ground lettuce per acre per year grown in California and harvested from three crops. Central to the Cornell project is the greenhouse’s computerized lighting system.
In one way, plants “see” the world much as humans do. That is, photosynthetically active radiation is located between 400 and 700 nm, which, for humans, is just inside the visible wavelength band. However, whereas the human eye is differentially sensitive to wavelength, plants perceive a photon at 400 nm much as they do a photon at 550 or 700 nm...
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