An increased demand for a consistent year-round supply of fresh, high-quality, and locally grown produce and the mitigation of food deserts has spurred interest in controlled environment agriculture (CEA) in greenhouses and indoor production facilities. However, the economic feasibility of indoor CEA is questionable due to high capital and operating costs. Although technology to manipulate light quanitity [radiation intensity and daily light integral (DLI)], mean daily temperature (MDT), and carbon dioxide (CO2) concentration exists, its utility is limited when growth, development, and biochemical responses are largely unknown for many specialty crops such as culinary herbs. Therefore, the research objectives were to 1) characterize historical controlled environment (CE) production trends and assess the current state of the United States (U.S.) hydroponics industry; and 2) quantify the growth, development, volatile organic compound (VOC) concentration, and consumer sensory preferences of finish-stage culinary herbs in response to DLI and MDT and of seedling responses to DLI and CO2. Our survey revealed large variation in production practices and technologies utilized. Growers identified research on manipulating the growing environment to improve flavor and the creation of production recipes taking multiple parameters into account as the highest priorities. Therefore, models characterizing growth and developmental responses of dill ‘Bouquet’ (Anethum graveolens), parsley ‘Giant of Italy’ (Petroselinum crispum), purple basil ‘Dark Opal’ (Ocimum basilicum), sage ‘Extrakta’ (Salvia officinalis), spearmint ‘Spanish’ (Mentha spicata), sweet basil ‘Nufar’ (Ocimum basilicum), and watercress (Nasturtium officinale) to MDT and DLI were developed. Surface regression equations estimated yield within the experimental range tested. These data will serve as a foundation, allowing growers to calculate and implement the most advantageous growing environment by taking growth, development, and energy costs into account. Altering MDT and DLI during CEA production not only influences crop growth and development, but can also affect VOC production and subsequently, consumer sensory attributes of sweet basil. Increasing MDT from 23 to 36 oC increased the concentrations of the phenylpropanoids eugenol and methyl chavicol and the terpenoid 1,8 cineole, but not linalool. However, the increase in MDT and VOC concentrations only influenced consumer appearance, texture, and color preference, but not aroma, flavor, or overall preference. We also quantified the extent radiation intensity and CO2 concentration during indoor seedling production influenced sweet basil yield and VOC concentration. Increasing radiation intensity from 100 to 600 μmol·m‒2·s‒1 increased 1,8 cineole, linalool, and eugenol concentrations. However, increased VOC concentrations were not correlated with increased consumer preference. Aftertaste, bitterness/sweetness, color, flavor, overall liking, and texture preference were highest when basil was grown under a radiation intensity of 200 μmol·m‒2·s‒1. This lead us to determine that consumers prefer the characteristic basil flavor made up of 1,8 cineole, eugenol, and linalool, which was not prevalent enough in basil grown under 100 μmol·m‒2·s‒1 but too high when grown under 400 and 600 μmol·m‒2·s‒1 leading to a lower consumer preference. Lastly, we quantified the extent radiation intensity and CO2 concentration during indoor seedling production affected basil yield and VOC accumulation at harvest. Seedling fresh mass was 284% greater when grown under 600 compared to 100 μmol·m‒2·s‒1. After being transplanted into a common greenhouse environment, both an 80% increase in fresh mass and increased eugenol concentration persisted. By concentrating resources during high density production phases, costs can be spread across many plants. Taking planting density and production duration into account, the increased lighting cost per plant during propagation can be as little as 5% of the same lighting during finishing. Together, these data can be used to improve yield, morphology, color, and flavor, potentially improving energy-use efficiency and the economic feasibility of CE culinary herb production.
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