It goes without saying that there's no smoking in class. But there is a good deal of sniffing of leaves, discussion of the finer points of inhaling and debate over which plant gives the biggest hit.

Welcome to Detroit's cannabis college, recently opened with courses on how to grow marijuana and harvest, cook and sell it too after Michigan legalised the drug as a medicine.

Students get instruction from horticulturalists, doctors and lawyers as well as hands-on experience cultivating plants and guidance on how to protect their stash from the criminal element.