
Light spectrum and light intensity, measured as photosynthetic photon flux density (PPFD), have a direct impact on yield and quality, says Fluence Bioengineering’s VP of Marketing Travis Williams, and adjusting these two elements to be in harmony with the other environmental parameters in a cultivation facility can help increase production beyond increased operating costs.
Results from a recent study ran by Fluence Bioengineering in collaboration with San Diego-based cannabis producer OutCo showed a near linear increase in trimmed flower weight with higher light intensities ranging from 400 to 1,200 PPFD. The study also found a 12-percent increase in total active cannabinoids under the broad-spectrum LED fixtures compared to HPS regardless of light intensity.
According to Williams, HPS spectrum was designed for industrial applications and not plant development, and traditional LED lights are typically magenta in color because red and blue are not only the most energy efficient wavelengths to produce, but they also coincide with the peak photoreceptors for chlorophyll-A and -B, which are the primary pigments for photosynthesis.
“The problem with that is, plants have a whole host of photoreceptors that are responsible for plant growth and development beyond chlorophyll,” he says. “Limiting a plant to narrow-band spectra reduces its ability to achieve full genetic potential.”
Light is used in two ways, Williams notes. It is used for plant growth, or biomass creation, and for plant development. Development consists of secondary metabolites (in the case of cannabis, these secondary metabolites manifest themselves as various cannabinoids such as THC and CBD and terpenes) and the morphology of the plant. Growers can alter the structural development of the plant and the chemical compounds inside it by using different wavelengths and intensities of light.
Fluence’s lighting systems use a broad spectrum of light, Williams says, which appears white to the human eye. This kind of spectrum targets all the photoreceptors within the plant to help it reach its peak genetic potential in terms of both growth and development, he says. However, he adds that the broad spectrum includes green light, which is less energy efficient to produce than red or blue light, but it leads to higher yield and higher biomass.
“At the end of the day, efficiency is about maximizing outputs while reducing inputs,” Williams says. “It’s not just about reducing inputs. Especially in the case of cannabis, growers need to always strive for improving production and also look at ways to achieve increases while reducing inputs."
“Overall production will be higher, margins will be higher and operating costs will be lower,” he says. “Growers can either charge the same price-per-pound and have higher margins, or they can reduce price as market and competition demands and still have healthy margins.”
Top photo courtesy of Fluence Bioengineering