The objective of these studies was to observe the effects of LED lighting treatments on physiological parameters of lettuce and microgreens. Four different lighting treatments; 1) Physiospec (white), 2) Red, 3) DR9 (25:75 Blue:Red), and 4) Anthospec (at 20/80 Blue:Red); were used in this experiment. Two experiments were conducted: 1) Examining the effects of LED lights on lettuce yield and photosynthetic activity and 2) The effects of switching lighting regiments halfway through the growth cycle on Kale microgreen yield and color. Physiospec lighting was found to promote the highest yield and photosynthetic activity among the four treatments for lettuce. It was found that changing from Physiospec lighting to Red lighting increased the fresh mass and stem height of kale microgreens. This also made the microgreens alighter shade of green.

Previous studies indicate that the degree of UV-Binduced photosynthetic inhibition may be highly dependent upon the photosynthetic photon flux density (PPFD, total quantum flux in the waveband 400-700 nm) incident on a plant. This study illustrates that Essex soybean leaves (Glycine max) preconditioned under high PPFD suffered less UV-B-induced photoinhibition than when preconditioned under low PPFD. However, sensitivity to UV-B increased when soybean leaves received high-PPFD as a concomitant treatment. The relative msgnitude of UV-B-induced damage was similar for both light-limited and light-saturated photosynthesis. This probably indicates that UV-B is inhibiting fundamentally different photosynthetic processes. Soybean leaves preconditioned under high PPFD had greater specific-leaf-weight, chlorophyll a/b ratio, and crude flavonoid content. The total chlorophyll concentration of soybean leaves preconditioned under high PPFD increased slightly over a UV-B irradiation period of five hours. Total chlorophyll concentration of leaves preconditioned under low PPFD decreased slightly in response to the same irradiation period.