Hemp has been cultivated for a wide variety of uses for over 4000 years. Industrial hemp is botanically the same plant as marijuana, except that industrial hemp has a delta-9-tetrahydrocannabinol (Δ9-THC) content of 0.3% or less. It originated in China for a variety of purposes and cloth and textiles and was also found to be used by ancient Egyptians. Vikings were known to create paper and sails from hemp and early versions of the bible were printed on paper produced from hemp (Vavilov, 1992; Lu and Clarke, 1995; Bouloc, 2013). Today, hemp is still cultivated for a myriad of uses – from cloth to food to cosmetics to biofuel. It also is cultivated for its phytocannabidiod content, including compounds such as cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN), which are purported to have many medicinal applications and benefits.
The United States also has a storied history with hemp. George Washington, the first president of the United States, was a hemp farmer at the famous Mount Vernon (Fike, 2016). The Declaration of Independence was written on hemp paper, and the first American flag was sewn from hemp cloth. Hemp was grown by many farmers in America for primarily food and seed and were even required by law to grow it in the 1600s. However, in 1937, hemp was taxed by the Marihuana Tax Act which effectively made it illegal to cultivate by way of excessive taxation. In 1970, all Cannabis was made federally illegal by the Controlled Substances Act as part of the war on drugs. In 2018, the United States Farm Bill allowed for cultivation of industrial hemp, which was defined as Cannabis sativa that contains no more than 0.3% delta-9-THC by weight.
Industrial hemp that is grown for fiber is generally produced by varieties that grow taller than other types of hemp which will allow for greater production of fiber in the tall stems of the plants. The stems of the plant produce long fibers that can be processed and later fashioned into textiles or fabrics, so the longer the stem the greater the fiber yield. Historically, hemp fiber has been used to produce clothes, paper, sails, ropes, plastics, and other items. Like all other industrial hemp, the delta-9-THC content must be less than 0.3% by weight. When growing industrial hemp for fiber, much higher planting densities are generally used than when growing for CBD production.
After the hemp is grown, plants are cut near the soil line and left in the field to undergo retting. Retting is a process that breaks down the bonds holding the fiber together and allows for easier separation of fiber from the core of the stem. After retting, the stalks are dried and the fiber can be separated from the stalk (generally by a machine) and can then be processed and spun into fiber strands.
Hemp seed has been grown as a food crop and is an excellent source of protein, fats, and antioxidants that is most often used as an animal feed. Industrial hemp grown for seed is generally planted at a moderate planting density when compared to industrial hemp used for fiber. Plants need to be monitored carefully for the best time to harvest: before the seeds begin to be dispersed to prevent loss of yield.
The tops of the plants are generally removed and run through a grain combine to harvest the seeds. Once harvested, the seeds should immediately be dried down to around 8% moisture to prevent mold and other problems.
Post-harvest, hemp seed can be used as a whole grain or dehulled. It can also be pressed to obtain hemp seed oil and seed cakes. Further processing can also be done to purify the grain into a protein powder.
Hulled hempseed, hempseed oil, and hemp protein powder are currently listed as GRAS (generally recognized as safe) substances by the federal Food and Drug Administration. These products are not considered to be consumable hemp products and are instead regulated as conventional food additives under the provisions of the state Food, Drug and Cosmetic Law (La R.S. 40: 602 et seq.) and Title 21 of the Code of Federal Regulations. More information on the GRAS Notices for these three product types may be found here.
Foods with hemp extracts or other hemp products added are regulated by LDH. All such additives must be registered as consumable hemp products with the Food and Drug Unit of LDH prior to use.
Industrial hemp can be used to produce two types of biofuel: bioethanol and biodiesel. Bioethanol is produced through a fermentation process, much like how ethanol is produced by corn and sugarcane. Biodiesel is made from the fats and oils acquired from pressing the seeds. The oil is then processed using a process known as transesterification (which is a chemical reaction between a vegetable or animal fat and alcohol with the aid of a catalyst) to produce biodiesel.
While industrial hemp grown for fiber, seed, and biofuel are generally cultivated using agronomic practices, industrial hemp grown for cannabidiol (CBD) and other minor cannabinoids should be treated more as a horticultural crop. Phytocannabinoids such as cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN) are believed to confer many health benefits. This remains an active area of research, but outside of certain approved pharmaceutical substances, no such effects have been demonstrated through rigorous scientific study. It is used in many different forms ranging from tinctures to lotions to edibles to tinctures and cosmetics.
Industrial hemp grown for cannabinoid production is an extremely labor-intensive crop but has the potential to be the most lucrative. The plants cultivated for cannabinoid production are grown for the unpollinated female flower, which requires growing only the female plants (generally from clones). Pollination of the female flower will lower the quality of the crop by reducing the amount of cannabinoids produced. Many varieties of industrial hemp were bred specifically for the production of CBD and other minor cannabinoids while producing a low delta-9-THC to CBD ratio. Because Cannabis plants with greater than 0.3% delta-9-THC are no longer considered industrial hemp as defined by the 2018 Farm Bill, they must be destroyed so proper variety selection is extremely important.
Act No. 336, a new law recently passed in Louisiana in 2021, added another clause that limits the entire THC (including other THC delta variants, like delta-8-THC and delta-10 -THC) content of any consumable hemp product to 1% by dry weight. The delta variants of THC like delta-9-THC have an intoxicating effect and can be produced from industrial hemp. The delta-9-THC limit is still 0.3% by weight. This is to prevent the sale of unregulated THC products that have recently gained popularity.