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Adding green [G (500–600 nm)] radiation to blue [B (400–500 nm)] and red [R (600–700 nm)] radiation creates white radiation and improves crop inspection at indoor farms. Although G radiation can drive photosynthesis and elicit the shade-avoidance response, its effects on plant growth and morphology have been inconsistent. We postulated G radiation would counter the suppression of crop growth and promotion of secondary metabolism by B radiation depending on the B photon flux density (PFD). Lettuce (Lactuca sativa ‘Rouxai’) was grown in a growth room under nine sole-source light-emitting diode (LED) treatments with a 20-hour photoperiod or in a greenhouse. At the same photosynthetic photon flux density [PPFD (400–700 nm)] of 180 μmol·m−2·s−1, plants were grown under warm-white LEDs or increasing B PFDs at 0, 20, 60, and 100 μmol·m−2·s−1 with or without substituting the remaining R radiation with 60 μmol·m−2·s−1 of G radiation. Biomass and leaf expansion were negatively correlated with the B PFD with or without G radiation. For example, increasing the B PFD decreased fresh and dry mass by up to 63% and 54%, respectively. The inclusion of G radiation did not affect shoot dry mass at 0 or 20 μmol·m−2·s−1 of B radiation, but it decreased it at 60 or 100 μmol·m−2·s−1 of B radiation. Results suggest that the shade-avoidance response is strongly elicited by low B radiation and repressed by high B radiation, rendering G radiation ineffective at controlling morphology. Moreover, substituting R radiation with G radiation likely reduced the quantum yield. Otherwise, G radiation barely influenced morphology, foliage coloration, essential nutrients, or sensory attributes regardless of the B PFD. Increasing the B PFD increased red foliage coloration and the concentrations of several macronutrients (e.g., nitrogen and magnesium) and micronutrients (e.g., zinc and copper). Consumers preferred plants grown under sole-source lighting over those grown in the greenhouse, which were more bitter and less acceptable, flavorful, and sweet. We concluded that lettuce phenotypes are primarily controlled by B radiation and that G radiation maintains or suppresses lettuce growth depending on the B PFD.

SummaryTwo photoselective and three photoluminescent greenhouse plastic films were studied for their effects on the spectral distribution of solar radiation and their influence on the growth of cherry and peach trees in the field and in laboratory tests.The two photoselective films modified the ratio of the photon fluence rate in the red to that in the far-red (R/FR), while the three photoluminescent films increased both the blue and red solar radiation by moving energy from the ultra-violet range to the blue and red wavelength range.The photoselective film that reduced the R/FR ratio, from 1.14 (open-field) to 0.93, enhanced shoot growth in peach (46.1 cm) and cherry trees (68.7 cm) compared to trees grown in the open-field (13.5 cm and 39.3 cm for peach and cherry trees, respectively). Trees grown under the red-emitting photoluminescent film showed increases in shoot length of 27.2 cm and 55.8 cm for peach and cherry trees, respectively; while plants grown under the blue-emitting photoluminescent film s...