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Sole-Source Lighting for Controlled-Environment AgricultureSince plants on Earth evolved under broad-spectrum solar radiation, anytime they are grown exclusively under electric lighting that does not contain all wavelengths in similar proportion to those in sunlight, plant appearance and size could be uniquely different. Nevertheless, plants have been grown for decades under fluorescent (FL) (1) + incandescent (IN) (2) lamps as a sole source of lighting (SSL), and researchers have become comfortable that, in certain proportions of FL + IN for a given species, plants can appear "normal" relative to their growth outdoors. The problem with using such traditional SSLs for commercial production typically is short lamp lifespans and not obtaining enough photosynthetically active radiation (PAR, 400-700 nm) when desired. These limitations led to supplementation of FL + IN lamp outputs with longer-lived, high-intensity discharge (HID) lamps in growth chambers (3). As researchers became comfortable that mixes of orange-biased high-pressure sodium (HPS) and blue-biased metal halide (MH) HIDs together also could give normal plant growth at higher intensities, growth chambers and phytotrons subsequently were equipped mainly with HID lamps, with their intense thermal output filtered out by ventilated light caps or thermal-controlled water barriers. For the most part, IN and HID lamps have found a home in commercial protected horticulture, usually for night-break photoperiod lighting (IN) or for seasonal supplemental lighting (mostly HPS) in greenhouses. However, lack of economically viable options for SSL have held back aspects of year-round indoor agriculture from taking off commercially.

Document ID
Acquisition Source
Kennedy Space Center
Document Type
Book Chapter
(Purdue Univ. West Lafayette, IN, United States)
Stutte, Gary W.
(Vencore Services and Solutions, Inc. Kennedy Space Center, FL, United States)
Date Acquired
June 2, 2015
Publication Date
May 31, 2015
Publication Information
Publisher: R. Lopez and E. Runkle, Meister Media Worldwide
Subject Category
Life Sciences (General)
Report/Patent Number
Funding Number(s)
Distribution Limits
Public Use Permitted.
Controlled-Environment Agriculture
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