Canadian University Studying Cannabis Cultivation

The University of Guelph may have published the first-ever paper on methods to improve cannabis cultivation.

Researchers from the University of Guelph, located in Ontario, Canada, shared their work in the October issue of the journal HortScience. The study  was funded in part by the Natural Sciences and Engineering Research Council of Canada. 

The researchers, Youbin Zheng, Mike Dixon, and Deron Caplan, attempted to find the optimal fertilizer rates for growing in soilless growing substrates commonly used in cannabis production during the vegetative stage of the plant. They focused on attempting to increase cannabinoid yield through increased concentration and botanical plant mass.

Researchers said the work is important because so much in cannabis hasn’t been analyzed by science.

“Growing marijuana has been illegal for so many years that there has been hardly any scientific research up until this point on how to produce this crop,” said Professor Youbin Zheng. “There has been no science guiding this industry.”

Some key findings of the study show that approximately 400 mg/L of nitrogen fertilization seems to be the peak for cannabis efficiency. Application rates over that caused decreases in THC content per gram, as well as yield per gram of the flower.

This first paper focused on the vegetative stages of cannabis growth, but a second paper, to be published in HortScience soon, will look at fertilizer rates and growth substrate conditions for flowering plants. The research team has moved on and is now studying lighting and irrigation factors in cannabis cultivation.

“Controlling the light spectrum, for example, provides the opportunity to standardize the concentration of cannabidiol, a chemical component in medical marijuana that appears to cause no intoxicating effects,” said Professor Dixon, director of the Controlled Environment Systems Research Facility.

The researchers and the university are positioning themselves to be leaders in the field of cannabis research.

“The University of Guelph is one of the top universities in the world for horticulture research, particularly for controlled environment plant production,” said Zheng, who holds the environmental horticulture chair in the School of Environmental Sciences. “We have the cutting-edge technology and the expertise to lead this area of research, and are well-positioned to train horticulturalists for the rapidly growing cannabis industry.”

“The University has studied medicinal cannabis production for scientific purposes for several years,” continued Zheng. “Recently proposed legislation means more licensed growers are seeking expertise. This has enabled us to have a more intense focus on this type of research.”