ASHS 2025 Conference

Microgreens have become popular due to their high nutritional value, quick production time, and versatile culinary applications. Color has been known to influence consumer purchasing habits but can also inform consumers perception of the nutritional quality. To improve the economic feasibility of controlled environment microgreen production, altering light intensity can be a tool to achieve the desired color and aesthetic profile of microgreens, improve yield, and increase nutritional quality. The objective of this research was to determine the effect of light intensity on the growth, color, and nutritional quality of ‘Red Rambo’ and ‘Daikon’ radish (Raphanus sativas) and ‘KX-1’ and ‘Toscano’ kale (Brassica oleracea), and the subsequent effect on consumer preference and perception of nutritional quality. Radish cultivars were grown for 7 days and Kale cultivars were grown for 14 days in 28 x 28 cm trays filled with a peat-based substrate, irrigated with 12N-1.8P-13.4K fertilizer at 100 ppm N supplemented with 15 ppm MgSO4 in reach-in growth chambers at 22 °C. Light intensities of 175 and 575 µmol·m−2·s−1 at a 16-h photoperiod were provided with broad-spectrum white LEDs. At harvest, growth and nutritional quality were quantified, and representative photographs were taken of each treatment to assess plant color. Photographs were then used in a survey of a representative population of the state of Tennessee made up of 821 participants. Consumers perceived higher nutritional content in the green ‘Daikon’ radish and ‘Toscano’ kale yet dark purple ‘Red Rambo’ radish and ‘KX-1’ kale, achieved with high intensity lighting, ranked higher for overall liking. These results were used in conjunction with appearance and nutritional quality data to assess consumer accuracy in identifying nutritional quality. Thus, the impact of light intensity on radish and kale microgreen appearance and nutritional quality can be linked to consumer perceptions to create effective production and marketing strategies for producers.