Controlled-environment (CE) production of vegetables, herbs, and leafy greens is quickly expanding to meet year-round consumer demand for fresh and local produce. However, knowledge gaps exist on how to manage growth and development of certain crops in CEs. Therefore, we evaluated developmental parameters of 10 different basil (Ocimum spp.) species and cultivars and 8 other herbs and leafy greens under a truncated 9-h short day (SD), day-extension lighting, and a 4-h night interruption utilizing red+white+far-red (R+W+FR) light-emitting diodes (LEDs) under a constant day/night temperature of 20 and 25 °C, respectively. All basil cultivars, with the exception of 'Red Rubin' can be classified as day-neutral plants (DNP) under a low photosynthetic daily light integral (DLI). Coriander, dill, lavender, and marjoram can be classified as facultative long-day plants (LDPs). While watercress, oregano 'Kirigami' and 'Greek', and spearmint can be categorized as obligate LDPs. Furthermore, six basil cultivars were evaluated under a 9-h SD and 16-h LD utilizing a moderate DLI of 224813 mol2219m-22219d-1 and a high DLI of 224823 mol2219m-22219d-1. For basil, DLI had a greater impact on development than day length. For instance, time to visible bud and open flower were hastened under high DLIs and node number below the first open flower were reduced indicating that basil exhibited a facultative irradiance response (FIR). Additionally, basil 'Genovese', 'Nufar', and 'Sweet Thai', exhibited a facultative LD response under moderate and high DLIs, while 'Red Rubin' exhibited a facultative SD response under low DLIs and a DN response under moderate and high DLIs. In a separate experiment, cucumber 'Elsie', tomato 'Climstar', and pepper 'Kathia' transplants were grown under LED supplemental lighting (SL) providing spectral qualities beyond B and R radiation. Fresh weight and leaf area of all three species was greater when G radiation replaced R and B radiation. However, other plant parameters evaluated in response to radiation quality were found to be species-specific. Results from these studies can provide growers with information on how to manage growth and development of vegetable transplants, culinary and ornamental herbs, and leafy greens in CEs.
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