Improving Cannabis Bud Quality and Yield with Subcanopy Lighting

Abstract

<jats:p>The influence of light spectral quality on cannabis (<jats:italic>Cannabis sativa</jats:italic> L.) development is not well defined. It stands to reason that tailoring light quality to the specific needs of cannabis may increase bud quality, consistency, and yield. In this study, <jats:italic>C. sativa</jats:italic> L. ‘WP:Med (Wappa)’ plants were grown with either no supplemental subcanopy lighting (SCL) (control), or with red/blue (“Red-Blue”) or red-green-blue (“RGB”) supplemental SCL. Both Red-Blue and RGB SCL significantly increased yield and concentration of total Δ<jats:sup>9</jats:sup>-tetrahydrocannabinol (Δ<jats:sup>9</jats:sup>-THC) in bud tissue from the lower plant canopy. In the lower canopy, RGB SCL significantly increased concentrations of α-pinine and borneol, whereas both Red-Blue and RGB SCL increased concentrations of <jats:italic>cis</jats:italic>-nerolidol compared with the control treatment. In the upper canopy, concentrations of α-pinine, limonene, myrcene, and linalool were significantly greater with RGB SCL than the control, and <jats:italic>cis</jats:italic>-nerolidol concentration was significantly greater in both Red-Blue and RGB SCL treated plants relative to the control. Red-Blue SCL yielded a consistently more stable metabolome profile between the upper and lower canopy than RGB or control treated plants, which had significant variation in cannabigerolic acid (CBGA) concentrations between the upper and lower canopies. Overall, both Red-Blue and RGB SCL treatments significantly increased yield more than the control treatment, RGB SCL had the greatest impact on modifying terpene content, and Red-Blue produced a more homogenous bud cannabinoid and terpene profile throughout the canopy. These findings will help to inform growers in selecting a production light quality to best help them meet their specific production goals.</jats:p>

Metabolic Profiling of Cannabis Secondary Metabolites for Evaluation of Optimal Postharvest Storage Conditions

“…The natural phytocannabinoids and terpenoids present in Cannabis are biosynthesized in the plant by specific enzymes. The compositions and concentrations of these molecules depend on the plant’s tissue-type, age, variety, growth conditions and harvest time ( Berman et al, 2018 ; Hawley et al, 2018 ; Welling et al, 2018 ; Bernstein et al, 2019a , b ; Namdar et al, 2019 ). Importantly, they also change over time postharvest, as a result of different degradation routes ( Trofin et al, 2011 , 2012 ; Peschel, 2016 ; Zamengo et al, 2019 ).…”

Cannabis Yield, Potency, and Leaf Photosynthesis Respond Differently to Increasing Light Levels in an Indoor Environment

“…Other studies had contradictory results on the effects of LI on potency. Hawley et al (2018) did not find canopy position effects on THC or CBD potency in a subcanopy lighting (SCL) trial, but they did find slightly higher cannabigerol potency in the upper canopy in the control (high pressure sodium top-lighting only) and the Red-Green-Blue SCL treatment, but not in the Red-Blue SCL treatment. While it is not possible to unlink spectrum from LI in their results, the magnitude of the reported potency differences, both between canopy positions and between lighting treatments, were relatively minor.…”

“…The linear increases in HI and AID with increasing LI both indicate shifts in biomass partitioning more in favor of generative tissues; a common response in herbaceous plants (Poorter et al, 2019) including cannabis (Hawley et al, 2018;Potter and Duncombe, 2012). The increases in these attributes under high LI may also indirectly facilitate harvesting, as there is correspondingly less unmarketable biomass to be processed and discarded, which is an especially labour-intensive aspect of cannabis harvesting.…”

Cannabis Indoor Growing Conditions, Management Practices, and Post-Harvest Treatment: A Review

“…In a recent study, subcanopy lighting (SCL) utilizing LED lights improved cannabis flower quality, consistency, and yield [30]. In this study, plants were not exposed to supplemental SCL or exposed to one of the two kinds of supplemental SCL spectra: red/blue (Red-Blue) and red-green-blue (RGB), positioned 15 cm to the side of the plant stem and raised 2 cm off the soil surface during the flowering stage.…”