Researchers in Canada are testing different cultivation variables to identify the ideal indoor growing conditions for medical marijuana. Photo by Gary C. Caskey/UPI | License Photo

Oct. 18 (UPI) -- Mention "weed paper" and people are likely to think the subject is something other than science. Not so for a group of horticulturalists in Canada.

Researchers at the University of Guelph, in Ontario, claim to have published the first scientific paper on marijuana cultivation in North America.


"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," Youbin Zheng, an assistant professor of environmental horticulture, said in a news release. "There has been no science guiding this industry."

Zheng and his colleagues tested a variety of fertilizer application rates and soil-free substrates to identify the ideal indoor growing conditions for medical marijuana. The test results revealed two ideal substrates and a superior rate of fertilizer application for high yields of plants rich in cannabidiol and THC, the prize components of medical marijuana.

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The researchers published their findings in the journal HortScience. A second paper, focusing on ideal indoor growing conditions during the marijuana plant's flowering stage, is scheduled to soon be published in the same journal.

Zheng and his research partners are now investigating how different types lighting and irrigation rates effect cannabis yields.

"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 Mike Dixon, director of the Controlled Environment Systems Research Facility at Guelph.

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Researchers say their findings could be eventually be used to grow food more efficiently.

In the United States, marijuana's classification by the DEA as Schedule 1 drug makes research involving the plant difficult. But the University of Michigan recently announced a new degree in marijuana studies, and as the weed-growing industry grows in states that have legalized the drug, the demand for better science is likely to follow.