Design issues for micropropagation lighting systems

Issues related to design of micropropagation lighting systems are investigated. Average photosynthetic photon flux (PPF) and mean relative deviation (MRD) are calculated using a previously developed model. A comparison of aisle versus aisle-free benching shows that the aisle-free configuration can deliver 60% higher PPF with the same energy input and without increasing the MRD. When compared to the presence of only one vessel, the presence of a full complement of micropropagation vessels on a shelf is shown to reduce PPF at the vessel lid level by 5.1% and at the plant level by 25.0%. Vessels were also found to attenuate radiation preferentially in the 300 to 400 nm range. Measurements of spectral power distribution along the lengths of fluorescent lamps show radiation output increases above 700 nm near the ends of the lamps. The implication that one can model and design for PPF, uniformity, and spectral quality is discussed.