What's the Difference Between Hemp and Marijuana?
I’ve been reading up on all things cannabis for years and until I started researching this topic for an agency client for whom I was creating content (read: ghost blogging for a hemp company), I was confused by hemp and its relationship to marijuana.
A word about terminology: Some feel the word “marijuana,” though obviously common parlance, has a racist (anti-Mexican) history. Some argue that we should reclaim the word in part because “cannabis,” while more scientific, is imprecise. I’m using the word “marijuana” here to differentiate what I’ve been smoking for decades — I didn’t start calling it “cannabis” until I realized that in industry circles, “cannabis” is the term of record — from hemp, which, as far as I can tell, has played little role in my life until CBD entered the picture.
Given that hemp and marijuana are both cannabis, it can be hard to tell them apart. To the casual observer, they look (and smell) the same. Moreover, they were lumped together by the federal government until the passage of the 2018 Farm Bill, which legalized the production of hemp in America after nearly 50 years of prohibition.
0.3% Is a Magic Number
Where hemp and marijuana fundamentally differ, at least as far as the U.S. government is concerned, is in their respective concentrations of the cannabinoid THC (tetrahydrocannabinol). When consumed in concentrations of more than 0.3%, THC produces psychoactive effects; when consumed in concentrations of less than 0.3%, it doesn’t.
The Farm Bill designated hemp as the member of the cannabis family with less than 0.3% THC. Because its THC content falls below the psychoactivity threshold, hemp can’t get you high.
Marijuana, then, is the member of the cannabis family with more than 0.3% THC (usually more than 5%). It can get you high and as such remains federally prohibited.
Which member of the cannabis clan is which can be perplexing even to people who work in the field (not to mention law enforcement), so let’s look at them schematically:
Cannabis → < 0.3% THC → not psychoactive → hemp → federally legal
Cannabis → > 0.3% THC → psychoactive → marijuana → federally prohibited
In addition to their physical similarities and one-time shared illegality, hemp and marijuana are both sources of the aforementioned cannabinoid CBD (cannabidiol) ― which does not produce psychoactive effects. In fact, it’s being used to treat two forms of epilepsy in children (via an FDA-approved formulation called Epidiolex), as well as pain, insomnia, anxiety and other medical conditions. CBD derived from hemp is no different from CBD derived from marijuana. Yet the Farm Bill has declared the former legal nationwide. CBD derived from marijuana? You won’t find that on the shelves of national retailers.
Hemp Grows Like a Weed
There are also differences in how hemp and marijuana are cultivated. Hemp is typically grown outdoors in multi-acre plots. Depending on what they’re being grown for, hemp plants can be separated by as little as four inches (they don’t generally need as much airflow between them as marijuana plants do).
With hemp, the farmer’s primary concerns are plant size and yield. “Since the stalk of the plant is harvested for industrial use, growers prioritize a taller plant. Records from colonial days mention stalks as high as 14 feet tall in Virginia,” notes National Geographic. “Growers who are after recreational or medicinal use, on the other hand, generally prefer shorter, leafier plants with more leaves and buds.”
To maintain a consistent level of THC, marijuana generally demands more attention. Temperature, lighting, humidity, CO2 and oxygen levels, as well as proximity to other plants, must be precisely controlled. For these reasons, marijuana is frequently grown indoors.
Another word about terminology: “Industrial” use (see Nat Geo above) does not include CBD, which in today’s hemp-growing climate is the tail that wags the dog — farmers growing hemp for CBD are making A LOT more money than farmers growing hemp for industrial uses (see 25,000 below). Because of this, hemp grown for CBD is cultivated somewhat differently than hemp grown for industrial purposes. (Woe to the grower whose CBD-bound hemp tests “hot,” with a THC concentration greater than 0.3%; the entire crop must be destroyed.)
The Hemp You Grew Up With? Imported
Hemp and marijuana also diverge in their status as an import. Even when the cultivation of hemp was illegal in the U.S., parts of the plant were legal to import. According to the Congressional Research Service, “Hemp imports to the United States — consisting of hemp seeds and fibers … for use in further manufacturing — totaled $67.3 million in 2017.”
Marijuana, by contrast, has never been legally imported into the U.S. That’s in large part because until California legalized it for medicinal use, in 1996, marijuana had been viewed primarily as an intoxicant, with strains bred for the highest-possible THC concentration.
Hemp seeds and fibers were imported because they can produce everything from food, fabric and fuel to paint, paper and plastic. There are some 25,000 applications for hemp. Even if THC were one day deemed the cure for cancer, marijuana is still unlikely to generate tens of thousands of uses.
When you consider that hemp was only recently declared federally legal and you need a scorecard to keep track of how cannabis is faring legally on the state (and local) level, it’s not surprising that people are confused by the similarities between hemp and marijuana.