Evaluation of Plasma Lights as a New Source of Light for Growing Selected Horticultural Crops In Controlled Environments

The spectral profile, radiant efficiency, and efficacy of plasma lights as new sources of artificial lighting were evaluated for growing selected horticultural crops in growth chambers. The spectral distribution of radiance from the plasma light source (Luxim Light Emitting Plasma, supplied by Chameleon Grow Systems) more closely approximated that of solar radiation compared to high pressure sodium (HPS), fluorescent (FL), metal halide (MH), or light emitting diode (LED) lamps. In a growth chamber, growth of 3 cultivars of tomato (Cobra, Roma, Totem) was measured under plasma light, a standard lighting system (FL plus incandescent lamps), and selected LED lamps. In general, plants grown under plasma light produced greater biomass and bloomed earlier compared to plants grown under other light sources. The yield and quality of fruits harvested are currently being determined. The efficacy of plasma lights is also being examined for culture of lettuce, spinach and other leafy vegetables. Estimations of radiant efficiency for producing PAR (photosynthetically active radiation) during the entire period of plant culture are being determined by monitoring electrical power usage by each lamp type. The high light intensities measured under the plasma lamps used in this study (2,756, 844, 469 µmol·m^-2·sec^-1 at 1, 2, 3 ft away from the light source, respectively) are particularly noteworthy. Results of this preliminary experiment suggest that the light emitting plasma lamps, whether used alone or in combination with other lamps, may provide effective artificial lighting for plant growth in controlled environments where increased light intensity is required.

•