Effects of Blue and Red LED Lighting Ratio on Yield and Quality Components of Broccoli and Radish Microgreens
Research Poster Health & Life Sciences 2025 Graduate ExhibitionPresentation by Aline Novaski Seffrin
Exhibition Number 111
Abstract
Microgreens have become increasingly popular due to their high nutrient content and health benefits. These crops are often grown indoors under LED lighting, where light quality is crucial in optimizing plant growth, yield, and nutritional value. Spectral manipulation has been identified as an effective strategy to enhance plant responses and resource use efficiency in controlled-environment agriculture. This study investigated the effects of combinations of blue and red LED light on the yield and nutritional composition of radish and broccoli microgreens. The microgreens were grown in a controlled-environment chamber with a 14-hour photoperiod under six LED treatments: 100% white, 100% red, 100% blue, and blue:red ratios of 50:50, 25:75, and 75:25, with an average photosynthetic photon flux density of 165 mol m2 s1. Radish and broccoli were harvested after 7 and 8 days, respectively. Microgreens grown under 100% blue, red, and white LED light exhibited taller shoots than those under mixed blue:red treatments, with 100% blue producing the tallest shoots. Dry biomass accumulation varied, with the lowest biomass observed under 100% blue LED light. Antioxidant activity was highest under 100% blue light, showing a 16.3% increase across both species, while 100% red light produced the lowest antioxidant levels. Microgreens under mixed blue:red treatments (50:50, 25:75, 75:25) showed 10.4% higher iron concentrations compared to those under monochromatic red, blue, or white light. These findings align with previous research on blue light's role in enhancing secondary metabolite accumulation and the impact of combined red and blue light on mineral uptake.
Importance
Light is fundamental for plant growth, development, and nutritional quality. Interest in indoor farming, especially in urban areas of the U.S. Northeast region, is growing due to its potential to support food and nutritional security. However, relying on artificial lighting as the sole source of radiation poses some challenges. Understanding how light quality and particularly the proportion of red and blue LED light impacts horticultural crops is critical for optimizing plant yield and quality performance and resource use efficiency. Our study reveals that manipulating the proportion of blue and red LED light makes it possible to optimize yield and enhance the quality and nutritional profile of nutrient-dense crops like microgreens.