LED Lighting: A Grower’s Guide to Light Spectra

For many growers, established and newcomers, the determination of the optimal light spectrum for growing crops can be challenging and highly dependent on crop species and variety. With the increased popularity of LED lighting, the capability to fine-tune a light spectrum has never been greater. Here, we break down the fundamental roles of the major spectral regions (ultraviolet, blue, green, red, and far-red) and explain the effect on plant growth, yield, and crop quality (i.e., greenness, coloration, flavor) when applied in isolation or combination. The first part of this review examines plant responses to light stimuli and the potential benefits for growers. We also discuss how LED lighting can be used to manipulate plant growth and development to improve crop productivity and/or value. We suggest some basic LED light “recipes” that could be used by growers to deliver specific growth effects and provide an easy-to-use visual reference guide. The second part of this review explores the impact of light treatments on crop productivity. Increased productivity is weighed against the ongoing costs associated with various light treatments, modeled in the context of UK electricity pricing.