LEDs are rapidly becoming the light source of choice for indoor horticulture connoisseurs. This is due to the ability of the light spectra of LEDs to be tailored to meet the nutritional needs of the plant – something traditional legacy horticulture lights cannot do.
Tessa Pocock PhD, a senior research scientist at the Centre for Lighting Enabled Systems and Applications (LESA) at Rensselaer Polytechnic Institute in NY, conducted a study to better understand the effect of customizable light sources and how this impacts plant growth. The study showed that the ability to customise the light spectra using LED lighting leads to many positive benefits. Benefits proven include greater energy efficiency, higher yield and improved concentrations of essential nutrients which contribute to human health.
In the study a red lettuce cultivar (Rouxai) was grown under different light treatments and compared against several key indicators: Yield (as determined by fresh weight), anthocyanin, carotenoid and chlorophyll concentrations and photochemistry. Yields were shown to be significantly higher in seedlings grown under Lime + Purple and Purple + Green LEDs compared to other light sources. Both LED combinations contain far red output (700 – 800 nm), and it is well accepted that far red increases cell elongation and leaf size. Additionally, higher anthocyanin and chlorophyll concentrations were also observed in these light combinations than other conventional light sources.
Conventional light sources operate on a “Photosynthetically Active Radiation” (PAR) spectra of 400nm to 700nm, meaning conventional lamps cannot target the far red (700 – 800nm) wavelengths that maximise yield in the same way customizable LEDs can.
Studies such as this demonstrate the significant advantages for the use of LEDs over traditional light sources for crops in indoor environments.
For more detail, read Tessa Pocock’s full white paper titled ‘Luxeon SunPus Series Lime LEDs Produce High Yield and Nutrition in Leafy Greens’ (https://www.lumileds.com/uploads/702/WP34-pdf) to learn more.