The term hemp is the vernacular English language word designating the plant Cannabis sativa, a plant that can be used to make a wide range of products, and be refined into a variety of commercial items, including paper, rope, textiles, clothing, biodegradable plastics, paint, insulation, biofuel, food, medicines, and animal feed. Along with bamboo, hemp is among the fastest growing plants on Earth and was also one of the first plants to be spun into usable fiber 50,000 years ago.
The term "hemp" has also traditionally been used as a generic name to refer to various fibrous plants, which have no botanical relation with Cannabis. These include Manila hemp, bog hemp, sisal hemp, New Zealand hemp, Deccan hemp, or Madras hemp (also at times called Indian hemp).
Regarding the Cannabis species, there remains two approaches depending on the region and the epoch, with term having various acceptions:
All forms of Cannabis (particularly in older texts), with types differentiated binomially (Winter hemp, Summer hemp, Indian hemp...); Some varieties of Cannabis: a subgroup of the varietals or cultivars of the Cannabis species; Only Cannabis plants grown as a source of fiber and/or seed (and not of the psychoactive resin contained in the plant's tops), Only Cannabis plants grown for certain "purposes", including contemporary industrial hemp which includes all parts of the plant (and might therefore include tops with substances such as cannabidiol)
The legality of hemp varies widely among countries, and with it, the definitions of the term. Globally, two approaches exist to understanding what the term "hemp" covers:
In most developed Western countries, governments regulate the concentration of the psychoactive component tetrahydrocannabinol (THC) and permit only a limited number of hemp cultivars, bred with an especially low THC content into commercial production. This is articulated with the view that a chemotype I (for higher-THC cannabis) represents a distinct cultivar as compared to the hemp chemotypes (II, III, IV, V) even though they are both Cannabis sativa. This amounts to a binomial separation, contained in U.S. legislation, where "hemp" and "marijuana" are mutually exclusive terms when referring to the plant and to its products. In many other regions of the world, in particular where hemp is a traditional crop, the distinction between chemotypes is not practiced by farmers and not contemplated in the law. In addition, local varieties, climate conditions, specific cultivation practices, and the absence of a system of intellectual property over seeds might impede any clear differentiation between "hemp" and non-"hemp" types of Cannabis, leading the UN Trade and Development to refer to these as "multipurpose hemp" where both lower- and higher-THC products can be harvested from hemp plants. In this view, hemp and marijuana are only distinct when referring to the finished products, but do not distinguish plant types.
Etymology
The etymology of hemp derives directly from the classical Greek () borrowed into Latin , and separately into Slavic and from there into Baltic, Finnish, and Germanic languages. Earlier etymologies are uncertain
In the Germanic languages, following Grimm's law, the "k" would have changed to "h" with the first Germanic sound shift, giving Proto-Germanic *hanapiz, which developed into the Old English form, , . Barber, however, argued that the spread of the name "kannabis" was due to its historically more recent plant use, starting from the south, around Iran, whereas non-THC varieties of hemp are older and prehistoric. Another possible source of origin is Assyrian , which was the name for a source of oil, fiber, and medicine in the 1st millennium BC.
Cognates of hemp in other Germanic languages include Dutch , Danish and Norwegian , Saterland Frisian , German , Icelandic and Swedish . In those languages, "hemp" can refer to either industrial fiber hemp or narcotic cannabis strains.
Uses
Hemp is used to make a wide range of commercial and industrial products. Hemp seeds are consumed directly as food and are also pressed into oil used for cooking, nutritional supplements, cosmetics, and as a drying oil in paints and varnishes. Hemp seed meal, a by-product of oil extraction, is increasingly evaluated for use in animal feed, including poultry, swine, cattle, fish, and companion animals, due to its favorable protein and fatty acid profile.
The bast fibers are applied in textiles and blended fabrics, furnishings, and specialty papers. They are also processed into composites for construction materials such as hempcrete, fiber-reinforced insulation panels, and biocomposites for furniture and automotive parts. Hemp fiber is additionally used in specialty products such as musical instruments, including guitars and amplifiers, and in pulp for paper and biodegradable packaging.
The inner woody core (hurds or shives) is employed in animal bedding, garden mulch, litter, and as a component in lightweight building blocks and particle boards. Hemp oil and extracts are also used for non-intoxicating cannabinoid products, such as cannabidiol (CBD), in dietary supplements, cosmetics, and wellness formulations.
Food
Hemp seeds can be eaten raw, ground into hemp meal, sprouted, or made into dried sprout powder. Hemp seeds can also be made into a slurry used for baking or beverages, such as hemp milk and tisanes. Hemp oil is cold-pressed from the seed and is high in unsaturated fatty acids.
In the UK, the Department for Environment, Food and Rural Affairs treats hemp as a purely non-food crop, but with proper licensing and proof of less than 0.3% THC concentration, hemp seeds can be imported for sowing or for sale as a food or food ingredient. In the US, hemp can be used legally in food products and, , was typically sold in health food stores or through mail order.
Nutrition
Hulled hemp seeds are 5% water, 5% carbohydrates, 49% fat, and 32% protein (table). In a reference amount of , hulled hemp seeds supply 586 calories of food energy, and are a rich source (20% or more of the Daily Value, DV) of several B vitamins and dietary minerals (table).
The share of protein obtained from hemp seeds can be increased by processing the seeds, such as by dehulling the seeds, or by using the meal or press cake (also called hemp seed flour) – the remaining fraction of hemp seed obtained after expelling its oil fraction. The proteins are mostly located in the inner layer of the seed, whereas the hull is poor in proteins, as it mostly contains the fiber.
The three main proteins in hemp seeds are edestin (83% of total protein content), albumin (13%), and beta-conglycinin (up to 5%). Hemp seed proteins are highly digestible compared to soy proteins when untreated (unheated). The amino acid profile of hemp seeds is comparable to the profiles of other protein-rich foods, such as meat, milk, eggs, and soy. The most abundant amino acid in hemp seed is glutamic acid (3.74–4.58% of whole seed) followed by arginine (2.28–3.10% of whole seed). Hemp seed protein has a profile of essential amino acids inferior to that of soy or casein.
Despite the rich nutrient content of hemp seeds, the seeds contain antinutritional compounds, including phytic acid, trypsin inhibitors, and tannins, in statistically significant concentrations.
Storage Hemp oil oxidizes and turns rancid within a short period if not stored properly; its shelf life is extended when it is stored in a dark airtight container and refrigerated. Both light and heat can degrade hemp oil.
Fiber Hemp fiber has been used extensively throughout history, with production peaking soon after being introduced to the New World. For centuries, items ranging from rope to fabrics to industrial materials were made from hemp fiber. Hemp was also commonly used to make sail canvas. The word "canvas" is derived from the word cannabis. Pure hemp has a texture similar to linen. Because of its versatility for use in a variety of products, today hemp is used in a number of consumer goods, including clothing, shoes, accessories, dog collars, and home wares. For clothing, in some instances, hemp is mixed with lyocell. Its benefits in terms of sustainability also increase its appeal in industries, such as the clothing industry.
Building material Hemp as a building construction material provides solutions to various issues facing current building standards. Its light weight, mold resistance, breathability, etc., make hemp products versatile in a multitude of uses. Following the co-heating tests of NNFCC Renewable House at the Building Research Establishment (BRE), hemp is reported to be a more sustainable material of construction than most building methods used today. In addition, its practical use in building construction could result in the reduction of both energy consumption costs and the creation of secondary pollutants.
In 2022, hemp-lime, also known as hempcrete, was accepted as a building material, along with methodologies for its use, by the International Code Council, and was included in the 2024 edition of the International Residential Code as an appendix: "Appendix BL Hemp-Lime (Hempcrete) Construction". This inclusion in the IRC model code is expected to promote expansion of the use and legitimacy of hemp-lime in construction in the United States.
The hemp market was at its largest during the 17th century. In the 19th century and onward, the market saw a decline during its rapid illegalization in many countries. Hemp has resurfaced in green building construction, primarily in Europe. The modern disputes regarding the legality of hemp lead to its main disadvantages: importing and regulating costs. Final Report on the Construction of the Hemp Houses at Haverhill, UK concludes that hemp construction exceeds the cost of traditional building materials by £48 per square meter.
Currently, the University of Bath researches the use of hemp-lime panel systems for construction. Funded by the European Union, the research tests panel design within its use in high-quality construction, on-site assembly, humidity and moisture penetration, temperature change, daily performance, and energy-saving documentation. The program, focusing on Britain, France, and Spain markets aims to perfect protocols of use and application, manufacturing, data gathering, certification for market use, as well as warranty and insurance.
The most common use of hemp-lime in building is by casting the hemp-hurd and lime mix while wet around a timber frame with temporary shuttering and tamping the mix to form a firm mass. After the removal of the temporary shuttering, the solidified hemp mix is then ready to be plastered with lime plaster.
Sustainability Hemp is classified under the green category of building design, primarily due to its positive effects on the environment. A few of its benefits include but are not limited to the suppression of weed growth, anti-erosion, reclamation properties, and the ability to remove poisonous substances and heavy metals from soil.
The use of hemp is beginning to gain popularity alongside other natural materials. This is because cannabis processing is done mechanically with minimal harmful effects on the environment. A part of what makes hemp sustainable is its minimal water usage and non-reliance on pesticides for proper growth. It is recyclable, non-toxic, and biodegradable, making hemp a popular choice in green building construction.
Hemp fiber is known to have high strength and durability, and has been known to be a good protector against vermin. The fiber can reinforce structures by embossing threads and cannabis shavers. Hemp has been involved more recently in the building industry, producing building construction materials including insulation, hempcrete, and varnishes.