A study by researchers at the Rutgers University reports that although light-emitting diode (LED) lighting can improve the growth of plants in greenhouses, standards are required to identify the optimal colors and intensity of light. The study could help enhance the energy efficiency of horticultural lighting products.
Several lighting companies frequently market their LED products with claims of providing an ideal “light recipe” which includes a combination of wavelengths and color ratios, for example, a 4-to-1 red to blue ratio on the spectrum (colors of a rainbow).
Usually, plant scientists make use of this information to assess the prospective effects of lamps on the growth and development of plants. However, as reported in a study to be published soon in the Acta Horticulturae journal, there is a lack of standardized processes for calculating these ratios.
The more efficient supplemental lighting sources are, the less electric power growers need to finish their crops. We hope to help make indoor crop production more sustainable and affordable.
A.J. Both, Study Senior Author, Department of Environmental Sciences, School of Environmental and Biological Sciences, Rutgers University–New Brunswick
According to Both, who is a professor and extension specialist in controlled environment engineering, an increase in energy efficiency can have huge effects on the result. He added that information related to novel crop lighting approaches will be helpful for the expanding indoor farming industry.
An earlier study headed by Both reports that electric lamps are used in controlled environments, and greenhouses, to supplement sunlight and increase lighting times for the production of horticultural crops such as herbs, flowers, and vegetables. The latest developments in energy-efficient LED technology to offer multiple lighting options for the horticultural industry.
However, it is not easy for growers to compare LED options and technologies, due to the lack of independent data relating to the performance of lamps. The research resulted in a prospective standardized product label, enabling lamps of different manufacturers to be compared.
The focus of Both and his team has continuously been on the independent evaluation of the performance metrics including light intensity, efficiency, power consumption, and the light distribution pattern, as well as the relay of this information to commercial growers.
According to Both’s study, the latest developments have offered enabled accurate control of the light from LED lamps, analyzing their effects on the growth and development of plants. Both and his colleagues worked together with plant scientists who analyzed the effect of light on ornamental crops or plants grown for food.
The new research advises the use of a spectroradiometer, an instrument that quantifies light output over a particular range of wavelengths. This instrument can be used to calculate different light ratios. The scientists reported considerable differences in light ratios when comparing sunlight with common lamps, such as an incandescent lamp, LED, fluorescent lamp, and high-pressure sodium lamp, used for plant lighting.
The scientists believe that their study will help to create standard definitions for particular wavebands (wavelength ranges) that are vital for the growth and development of plants.
Timothy Shelford, a part-time research specialist at Rutgers, is the lead author of the new study. Shelford is also associated with Cornell University. Claude Wallace, a Rutgers graduate, and part-time employee, also participated in the research.