Although hemp and marijuana are both varieties of cannabis, there is a difference between them. The differences between these cannabis varieties are primarily evident in the way each plant is used. These differences are also documented in the language, laws, and regulations that apply to each variety. In this introduction to hemp, we’ll break down the anatomy, history, use, and legality of the hemp plant to get to the heart of not only what distinguishes it from marijuana, but also what makes it such a viable, versatile commodity.
What Is Hemp?
Hemp plants are varieties of Cannabis sativa L. Hemp is a dioecious plant, which means it can be separated into male and female plants. Hemp plants have served a wide variety of purposes for more than 10,000 years for fiber (from the plant’s stems) and protein (from hemp seeds). Hemp fibers can be used to make countless household items, including paper, clothing, furnishing fabric, rope, food, and building materials.
Hemp varieties of cannabis don’t produce high amounts of tetrahydrocannabinol (THC), the intoxicating cannabinoid in marijuana, but they are capable of producing the non-intoxicating and medicinally rich cannabidiol (CBD) in high concentrations.
Many countries differentiate between marijuana and hemp by the amount of THC produced per weight of a dry plant. In the U.S., industrial hemp is defined as “the plant Cannabis sativa L. and any part of such plant, whether growing or not, with a delta-9 THC concentration of not more than 0.3 percent on a dry weight basis.” The European Union has set the limit at 0.2 percent, while in Great Britain the limit is zero, unless you have a cultivation license to grow industrial hemp with no more than 0.2% THC.
The whole hemp plant — from stalk to seeds — can be used to make fuel and feedstock. For more specific applications, hemp can be divided into four categories:
- Bast Fibers
- Hurds, or shives
- Leaves and flowers
Can Hemp Get You High?
Hemp isn’t completely absent of psychoactive compounds, but that doesn’t mean it will get you high. Hemp plants simply don’t produce enough THC to have an intoxicating effect. CBD, though psychoactive, is a non-intoxicating cannabinoid and won’t produce any form of a euphoric high on its own. In other words, hemp has plenty of therapeutic potential, but you’ll have to look elsewhere if you want to get high.
How are Hemp Varieties Chosen?
Depending on the desired final product, hemp cultivars are chosen based on several factors, including:
- Stem quality
- Cannabinoid content
- Resistance to disease
- Time to harvest
- Hemp oil content
- Seed production per acre
CBD production, in particular, has become a major factor in recent years. As the CBD market continues to grow, more and more cultivars are also being chosen based on their CBD production and unique aromatic, or terpene, profiles.
How is Hemp Used as a Food Product?
Hemp seeds are rich in protein, dietary fiber, vitamins, and minerals. They contain an optimal ratio of omega-6 to omega-3 fatty acids for healthful consumption. A 2008 study also found that hemp proteins are more digestible for humans than common soy protein isolates (SPIs) used in food products.
Hemp can be consumed in either raw seed or a hemp oil form. Hemp oil is pressed from the seeds for a concentration of protein. Both food product forms of hemp are utilizing hempseed as a nutritional resource. Hemp seeds can also be ground into flour or mixed with water to create hempseed milk.
How Are Hemp Fibers and Leaves Used?
CBD oil is extracted from hemp leaves, flowers, and branch tips. The CBD oil extracted from hemp can be used to treat a wide variety of ailments, hence the ever-growing popularity of CBD-focused hemp cultivation.
Hemp fibers are primarily used for textiles, paper, building materials, and other industrial products. Hurds, or shives, are short woody hemp fibers typically found inside the stalk. They’re used to make hempcrete, bedding materials, absorbents, particle board, ceiling panels, compost, and other industrial products. Bast fibers make up the outer portion of the stalk and are typically split into three categories — primary, or line fiber, secondary, and the tow. They are categorized according to their cell strength and cell wall thickness, which will determine the fiber’s strength, durability, and ultimately what the it can be used for.
How is Hemp Processed?
Many types of processing techniques are utilized to process hemp seeds and stalks. The technique used depends on the purpose of the final product.
Hemp seeds can be consumed whole, or refined by being pressed or crushed to produce hempseed oil and hemp flour. Hemp seeds are also hulled, or shelled, to make them more palatable. The remaining shells, which are rich in fiber, can also be used to make flour.
Hemp stalks are processed through decorticating, a multistep method for removing the long fibers from the rest of the plant. The steps taken during the intermediate processing period include:
Hemp stalks have tough cellular tissue that makes up their surface and must be dissolved through a process called retting. There are three modes of retting:
- Field Retting: Cutting the hemp plants and laying them on the field for four (4) to six (6) weeks, turning periodically. During this time, any bacteria on the plant’s surface will break down the outer layer of the stalk. The retted stalks are then dried.
- Water Retting: The stalks are immediately dried after harvesting, then placed into water for a few days. The water is used to soften the outer layer of the stalks and to help promote the growth of additional bacteria which helps accelerate the process.
- Chemical Retting: Using acids, bases, and special enzymes to break down the compounds that hold together the strong bast fibers.
All retted stalks should be dried until they have less than 15% moisture. Anything above 15% can potentially harbor and promote the growth of fungi and bacteria. If the stalks get too dry, meaning less than 10% moisture, they can become too brittle to transport.
The decorticating process typically involves three stages:
- Scutching: Passing the stalks through a series of rollers to break apart the hemp fibers. During this step, the woody core is pushed out and separated from the pliable fibers. This is another step where proper drying comes into play. The sweet spot between 10 and 15% moisture is key here. If the stalks are too dry, they will be crushed into a powder. If they are too moist, they won’t break and separate properly.
- Hackling: Combing the short and intermediate fibers out of the stalk.
- Twisting: Individually twisting the fibers into yarn.
Modern decorticating techniques employ steam explosion (treating the fibers with steam through a pressurized chamber) and ultrasonic breaking (breaking down fibers using ultrasonic waves) to maintain the integrity of the fibers throughout the process. These techniques are not as harsh on the stalks and allow processors to use the fibers on cotton and wool processing machinery.
Baling and Storing
Hemp stalk is baled for transportation and long-term storage using traditional farming balers. Large round balers are best for hemp because they don’t pack the hemp as tightly as square balers, which allows for more thorough drying. Hemp should be stored in a dry environment in conditions intended to reduce as much absorbable air moisture as possible. It’s also important to check for wet patches during baling to further avoid mold.
How is Hemp Cultivated Differently than Marijuana?
Male hemp plants flower much faster than females and do not produce nearly as much fiber. In stark contrast to marijuana fields, most female hemp fields include sporadically placed males. The male hemp plants release pollen for the female hemp plant to produce seeds that will either be used for future crops or sold as food. In marijuana fields, males are typically eliminated to ensure the maximum production of sensimilla flowers.
While marijuana cultivation requires ample spacing to reduce the risk of mold or bacteria, hemp can be planted more densely. Most marijuana crops are planted at one (1) plant per four (4) square feet. Hemp plants that are grown for hemp oil are planted at roughly 40 to 60 plants per four (4) square feet. Hemp plants grown for fiber are even more densely planted at a rate of about 100 to 120 plants per four (4) square feet.
Hemp plants are almost always cultivated outdoors, as opposed to marijuana plants, which are mostly planted in greenhouse or indoor settings. Because hemp is susceptible to the same predators diseases and insects that attack marijuana, the hemp industry employs a technique called crop rotation, in which alternating crops are planted in the same place, to avoid any buildup of these organisms and allow nutrients to return to the soil. The specific order of crop rotation and types of crops being rotated with hemp will depend on the location of the farm. Hemp is also used as a rotational crop at farms where it is not the primary agricultural product.
Is Hemp Cultivation Legal in the U.S.?
The 2014 Agricultural Act, more commonly known as the 2014 Farm Bill, signed by Democratic President Barack Obama, includes section 7606, which allows for universities and state departments of agriculture to cultivate industrial hemp, as long as it is cultivated for the purpose of research. State departments and universities must also be registered with their state, and defer to state laws and regulations for approval to grow hemp.
Of the 41 states that have passed industrial hemp-related legislation, 39 have legalized statewide hemp cultivation programs that define hemp specifically to differentiate it from marijuana, establish licensing requirements, and regulate production.
World History of Hemp
Hemp has been cultivated on a global scale for thousands of years. The oldest documented evidence of hemp cultivation is a hemp rope found in the Czech Republic, which dates back to 26,900 BCE.
Some of the earliest known prolific uses of hemp began in China about 10,000 BCE, where hemp was used to make clothing, rope, and paper. The Yangshao culture, which existed in China from roughly 5000 BCE, wove hemp and pressed it into their pottery for decorative purposes. From about 5,000 to 300 BCE, hemp was also grown in Japan for fiber and paper.
Cannabis played a large role in the Greco-Roman cultures as a source of both fiber, an intoxicant, and a medicine. Cannabis seeds were discovered in the ruins of Pompeii, and Greek rhetorician Athenaeus made note of hemp being used to make rope between 170 and 230 CE. Roman author and naturalist Pliny the Elder also made reference to a cannabis root decoction as a treatment for joint stiffness and gout in the first (1st) century.
Exactly how and when hemp originated in the New World is still highly debated. Though long thought to be introduced to the Americas by Christopher Columbus, hemp has been discovered in Native American civilizations that predate Columbus’ arrival. William Henry Holmes’ “Prehistoric Textile Art of Eastern United States” report from 1896 notes hemp from Native American tribes of the Great Lakes and Mississippi Valley. Hemp products from pre-Columbian native civilizations were also found in Virginia. Vikings, who depended on hemp for making rope and sails, may also have brought hemp seeds with them when they attempted to colonize the New World.
Jamestown settlers introduced hemp to colonial America for rope, paper, and other fiber-based products; and even imposed fines on those who didn’t produce hemp in the early 1600s. Both U.S. presidents George Washington and Thomas Jefferson grew hemp.
Hemp was a prominent crop in the United States until 1937, when the Marihuana Tax Act virtually obliterated the American hemp industry. During World War II, hemp saw a resurgence in the U.S., as it was used extensively to make military items ranging from uniforms to canvas and rope. The United States Department of Agriculture even released a short documentary, “Hemp for Victory,” in 1942, which promoted hemp as a useful crop for the war cause.
The World War II hemp resurgence was short-lived, though. Until the passing of the 2014 Farm Bill, the Controlled Substances Act of 1970 kept industrial hemp production dormant. Today, hemp is rapidly becoming an indispensable resource for CBD oil and other CBD products.