Effect of Blue and/or Green Wavelength-specific White LED Lighting on Growth and Development of Tomato in Indoor Farming Systems

Abstract

White light-emitting diodes (LEDs), the most commonly used artificial light source in indoor farming systems, require spectrum optimization for crop-specific responses. This study evaluated the effects of wavelength-specific blue and green modifications on tomato growth, productivity, and fruit quality. Treatments included normal white LEDs (NWL), two wavelength-specific white LEDs (SWL1 and SWL2), and a red + blue LED combination as control. NWL represented a broad-spectrum baseline, SWL1 was enriched in red and longgreen wavelengths, SWL2 emphasized blue and short-green wavelengths, and the red+blue combination served as a conventional control. Both SWL treatments enhanced biomass, leaf area, and fruit yield relative to the control. In particular, SWL1 increased fruit number (+38%), total yield (+48%),° Brix (+16%), and reducing sugar (+30%) relative to the control. SWL2 improved fruit number and yield by 23% and 26%, respectively, but did not enhance° Brix or reducing sugar. In addition, fruits from SWL1 showed higher antioxidant capacity, consistent with elevated lycopene accumulation. Yield and sugar gains under SWL1 suggest that spectral tuning toward long-green wavelengths promotes assimilate partitioning into fruit. Moreover, SWL1 demonstrated superior light use efficiency and energy use efficiency. These findings suggest that tailoring the spectral peaks of white LEDs, particularly in the blue and green regions, can enhance tomato productivity and fruit quality. Wavelength-specific full-spectrum lighting therefore represents a promising strategy for high-efficiency tomato cultivation and provides a practical lighting solution to reduce energy costs while improving crop value in indoor farming systems. © 2025, American Society for Horticultural Science. All rights reserved.