LED Lighting Provides Energy Efficiency, But Needs Standards

With the growing popularity of LED lighting, scientists are looking to study its effects on plant growth. However, a lack of standards has made studies unreliable.

While LED lighting can enhance plant growth in greenhouses, standards are needed to determine the optimal intensity and colors of light, according to research from Rutgers University that could help improve the energy efficiency of horticultural lighting products.

White LED lamps are used to improve basil production in a greenhouse. Courtesy of A.J. Both/Rutgers University-New Brunswick.

Many lighting companies market their LED products with claims of delivering an optimal “light recipe” that often consists of a combination of wavelengths and color ratios, such as 4-to-1 red-to-blue ratio on the spectrum. Plant scientists often use this information to evaluate the potential effects of lamps on plant growth and development. But standardized procedures on how to calculate these ratios are lacking, according to a study soon to be published in the journal Acta Horticulturae.

The study recommends using a spectroradiometer, an instrument that measures light output across a specific range of wavelengths. The researchers reported substantial differences in light ratios comparing sunlight with common lamps, including LED, high-pressure sodium, incandescent, and fluorescent lamps used for plant lighting. The researchers hope that their work will contribute to the development of standard definitions for specific wavebands (ranges of wavelengths) that are important for plant growth and development.

Senior author A.J. Both and colleagues continue to focus on independently assessing performance metrics such as power consumption, efficiency, light intensity, and the light distribution pattern, and relaying that information to commercial growers. Recent advancements have provided opportunities to precisely control the light from LED lamps and study their impacts on plant growth and development, according to Both’s research.

“The more efficient supplemental lighting sources are, the less electric power growers need to finish their crops,” said Both, a professor and extension specialist in controlled environment engineering at Rutgers. “We hope to help make indoor crop production more sustainable and affordable.”

Increased energy efficiency can have a big impact on the bottom line, and information about new crop lighting strategies will help the burgeoning indoor farming industry, Both said.