What is the difference between cannabis and hemp?

“Surely no member of the vegetable kingdom has ever been more misunderstood than hemp.” -David P. West in a report for the North American Industrial Hemp Council in 1998.

What is the difference between cannabis and hemp? In a word, semantics. From a practical standpoint, it’s the THC concentration.

Cannabis and hemp are, scientifically speaking, the same plant. They share the same genus, Cannabis, and the same species, Sativa. Given that they are the same plant, it’s fair to ask why they’re viewed and treated so differently. The difference comes in breeding and use. Humans co-evolved with the cannabis plant. In fact, humans and cannabis are so intertwined that linguists often use a culture’s word for cannabis to trace the history of its language.

Humans have bred cannabis for different uses. It’s widely known that cannabis can produce fiber for clothing, paper, and construction. Its trichomes produce cannabinoids, including cannibidiol (CBD), which have multifarious medical uses. And, of course, the most well-known cannabinoid, delta 9 Tetrahydrocannabinol, commonly referred to as “THC”, is used daily across the world as an intoxicant, spiritual aid, and medicine.

THC is only produced in the female plant. For this reason, some people understandably assume that hemp only comes from male cannabis sativa plants. But, female plants can be “hemp” plants, too. The difference is what cannabinoid is predominant in the particular strain. Generally speaking, a cannabis sativa plant that is CBD dominant, as opposed to THC dominant, is a hemp plant. From a scientific perspective, this is probably the most accurate distinction. However, legal definitions, which matter in practical usage, tend to focus on pinning down the THC to a percentage point. In the 2014 US Farm bill Congress defines hemp as “the plant Cannabis sativa L. and any part of such plant, whether growing or not, with a [THC] concentration of not more than 0.3 percent on a dry weight basis.” Most states that have enacted hemp laws mimic the Federal definition.

Interestingly, this 0.3% THC ceiling, which is the current world-standard, is based on the work of Canadian scientist Ernst Small, who conducted research on cannabis and published “The Species Problem with Cannabis” in 1971. In his book, Small stated that there isn’t a natural point at which the cannabinoid content could be used to distinguish strains of hemp and cannabis. Despite this he drew an arbitrary line on the continuum of cannabis types, and simply decided that 0.3 percent THC was the proper line. The line has held.

Despite being a dubious and unscientific distinction, it is likely that the 0.3% THC level will become the norm as more states roll out hemp legislation. For this reason, testing and quality control will be vitally important to hemp farmers and manufacturers of hemp-based products.