Comparison of fluorescent lamps as an energy source for production of tomato plants in a controlled environment

Abstract

The relative efficiency of 12 fluorescent lamps used for growing tomato seedlings in a controlled-environment chamber was investigated. Fresh weight, dry weight, leaf area and plant height were recorded and compared to the incident radiation flux. The highest fresh weight, dry weight and leaf area were found under Philips TL 33 and TL 83 when compared on the basis of equal wattage input. TL 33 also produced the most compact plants expressed as mg dry wt. per cm height. Fresh or dry weight production was not closely correlated to the measured incident photosynthetic photon flux (PPF), which indicates that light quality or specific energy distribution is an important factor. The highest relative efficiency (g mol CO 2 × 100/mol abs.) was found under a combination of TL 27 + Osram L-Fluora, although this higher efficiency was not great enough to counteract the lower radiation flux emitted. The findings show that the efficiency of the lamps to convert electrical power to visible radiation is not a reliable criterion for the selection of lamps for plant illumination.