Toronto police said Ping Jiang, 44, had 2,200 more plants than permitted at a commercial location in Leslieville. The plants had a street value of about $2.2 million, the Toronto Star reported Wednesday.
Police charged in a statement the excess plants were intended for drug trafficking.
The Canadian government issues three types of licenses for medical marijuana, but officials say the system is rampant with abuse, often by gangs and organized crime groups.
The Royal Canadian Mounted Police estimate more than 50 percent of operations that grow medical marijuana have ties to people convicted of producing or trafficking in drugs.
During the raid in Leslieville, police also seized more than 44 pounds of dry marijuana.