10) Cannabis Terpene Levels: Indoor Growing vs. Outdoor Growing

The growing acceptance of cannabis as a therapeutic agent has sparked interest in the plant's bioactive or healing molecules, with cannabinoids and terpenes being the focus of discussion. Therefore, factors influencing a strain's cannabinoid and terpene profile have become of great importance. A recently concluded study found that cannabis is only as good as the growing environment, and therefore potency fluctuates depending on environmental factors. This reinforces the ancestral belief that it is indeed nurture, and not just nature, that determines the characteristics of a living being..

Traditionally, cannabis has been grown outdoors by local communities and historic cultivators. But with the popularization of cannabis, demand has increased, forcing cultivators to explore indoor cultivation which allows for year-round cultivation. Unconsciously and as this study revealed, the chemical composition of cannabis has also undergone significant changes.

Study details

A group of researchers from Columbia University in New York, in collaboration with the owners of three cannabis companies – Huckleberry Hill Farms, Moon Made Farms and Novato's Cosmic View – conducted a study comparing the cannabinoid and terpene profile of cannabis under natural and artificial growing environments. The results of the study were published in the journalMolecules in January 2023.

The researchers grew six cannabis plants from two genetically identical cultivars: Red Velvet and Cheetah Piss. Three plants were grown outdoors in "living" soil and natural sunlight, while the other three plants were grown indoors with artificial light and an artificial growing medium. When the plants were ready to harvest, the researchers selected buds of similar size and morphology from the top third of the plants. Gas chromatography-mass spectrometry (GC-MS) was used to analyze terpenes, while ultra-high performance liquid chromatography (UPLC-MS) was used to analyze cannabinoids.

Cannabis grown outdoors has higher terpene levels

Researchers found that cannabis grown outdoors had a greater diversity of terpenes, which were also found in higher concentrations. They reported “remarkably higher” levels of the following beneficial terpenes:

• Limonene

• Β-myrcene

• Β- caryophyllene

• Α-humulene

• Α-bergamoten

• Α-guaiene

• Germacrene B

The research also found an “increased preponderance of sesquiterpenes” in cannabis grown outdoors. There was only a slight difference between the cannabinoid profiles of cannabis grown indoors and outdoors. Cannabis grown indoors had a higher concentration of oxidized and degraded cannabinoids. The researchers explained that this could be due to lower terpene levels in the indoor samples, with terpenes acting as antioxidants. The levels of cannabigerolic acid (CBGA) and cannabidiolic acid (CBDA) were almost similar between the two groups. Cannabichromenic acid (CBCA) was slightly higher in outdoor plants, while tetrahydrocannabutolic acid (THCBA) was higher in indoor plants.

Need to explore more outdoor growing

Most commercial growers grow cannabis in indoor environments that allow them to manipulate and optimize production. Unfortunately, this can result in a less robust terpene profile. With research now highlighting the importance of terpenes in a strain, there is a need to reimagine and reinvent outdoor cultivation as the next frontier in commercial cannabis production.

Conclusion

In summary, this study highlights the significant impact of growing environment on the chemical composition of cannabis, particularly on terpene levels. The results highlight that cannabis grown outdoors has a greater diversity and concentration of beneficial terpenes compared to that grown indoors. This discovery is crucial for cannabis producers seeking to maximize the therapeutic properties of their products. As the demand for high-quality cannabis continues to grow, it becomes essential to reconsider cultivation methods and explore the potential benefits of outdoor cultivation. Ultimately, the key to producing cannabis with optimal chemical profiles may lie in a balance between traditional techniques and modern cultivation innovations.