The Value of Far-Red in LED Grow Lights for Cannabis Crops

Far-red light has recently become a bit of a buzzword in cannabis cultivation. However, despite years of reports from growers about the value of red light on development yields, it's only recently that plant researchers have legally been able to study this effect on a regulated crop.

TSRgrow's advanced LED lighting system has always had a full-spectrum approach to horticultural lighting. Since day one, our products have incorporated blues, reds, greens, and far-reds, so the virtue of far-red lighting is not news to us. 

But these most recent scientific developments are worth highlighting, as they are changing how indoor growers approach plant morphology and flower production.

Moving Beyond PAR: Photosynthesis Demands ePAR

Cannabis aside for a moment, plant scientists have always thought that most plant species used photosynthetically active radiation (PAR) for photosynthesis. Traditionally, PAR described photons traveling at wavelengths between 400 to 700 nm, which closely relates to the narrow band of light visible to humans. 

Chlorophyll, the green compound in leaves that absorbs sunlight, primarily absorbs blue and red wavelengths (420−450 nm and 600−700 nm, respectively). It's why conventional LED grow lights advertise the blue-red wavelengths, as these have always been considered the most valuable wavelengths for improving yields in indoor cultivation.

However, research into far-red supplementation for conventional crops, like tomatoes and lettuce, slowly began shifting the scientific perspective on PAR. For example, studies have already determined that far-red light grows larger tomatoes and increases the total biomass of lettuce

The discovery that plants may utilize a broader light spectrum than previously thought led to a new hypothesis: extended PAR or ePAR. This idea considers that plants work with light from 400 to 750 nm during photosynthesis. 

With a better understanding of far-red light on other crops, there is new research exploring the applications for cannabis cultivation as well — and the results are underscoring what growers have reported for years.

Red and Blue are Overrated: New Research Underscores Value of Far-Red for Cannabis

Thanks to the 2018 Farm Bill, which legalized the production and study of hemp, there are now much lower regulatory hurdles for federally funded institutions to study low-THC cannabis cultivars. This has opened up the door for much more robust exploration of the drivers behind cannabis growth and cannabinoid development.

Recently, Shuyang Zhen, Marc W. van Iersel, and Bruce Bugbee, researchers at Utah State University, published "Photosynthesis in sun and shade: the surprising importance of far-red photons." Their discovery has been nothing short of paradigm-changing for the indoor cannabis sector.

Firstly, as co-author Bugbee explained to the Cannabis Business Times, there has been too much focus on blue and red lighting for indoor cultivation. Even though it's true that chlorophyll primarily absorbs these wavelengths, this is only half of the story. 

Bugbee's team isn't the only one pursuing this idea. Many cannabis-specific investigations, including a 2021 publication in Industrial Crops and Products, have found more "beneficial effects of full-spectrum (white light) to plant growth and function, compared to monochromatic red and blue lights."

As per Bugbee, "The effect of color on photosynthesis is way overrated [and] conversely, the effect of color on plant shape is underrated." To this end, he believes that far-red lighting likely has significant applications for indoor cannabis cultivation precisely because of its ability to manipulate plant shape. 

Plant morphology is a critical consideration in indoor settings due to space constraints. Instead of the towering tree-like plants seen in outdoor cannabis cultivation, indoor growers strive to grow short, stocky plant shapes that better suit a small enclosed space. Bugbee explained in a later interview with Cannabis Business Times that "In addition to photosynthesis, far-red photons are a powerful tool to manipulate plant shape."

This need to control plant morphology in an indoor setting is part of why far-red lighting is suddenly front and center in the discussion about cannabis grow lights. 

Pioneers of Far-Red Spectrum for Cannabis Cultivation

The Value of Far-Red in LED Grow Lights for Cannabis Crops (1)Far-red light for cannabis cultivation may be suddenly trending, but it's part of the foundation of the TSRgrow line of full-spectrum LED fixtures.

From the start, our commercial horticulture LED lighting solutions have always had full-spectrum capability — including far-red. During our early product development phase, we worked closely with plant scientists and academics to develop a product encompassing the entire spectrum of photosynthetic requirements, including red, blue, green, and — of course — far-red. With limited power to deliver effective photons to the plant in an indoor setting, it's imperative to blend the correct ratios of spectrums so that the wavelengths that are delivered are 100% utilized and effective for the plants being grown.  Spectrums and the ratios of wavelengths to each other play a crucial role in cultivation.  TSRgrow has always incorporated far-red in its flower spectrums - and customers consistently achieve the highest TAC and THC.

Our advanced high-powered LED light fixtures feature centralized power to remove heat from the grow room, allow for Plug’n Play replacement and deliver integrated dimming and control with no dimming wires. Engineered to efficiently deliver full-spectrum photons — to make every watt count in the grow room.

Contact TSRgrow today, to learn how our advanced LED lighting solutions can help your commercial cultivation facility succeed. 

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