Hemp (from Old English hænep, see cannabis (etymology)) is the common name for plants of the entire genus Cannabis, although the term is often used to refer only to Cannabis strains cultivated for industrial (non-drug) use.
Industrial hemp has many uses, including paper, textiles, biodegradable plastics, health food, and fuel. It is one of the fastest growing biomasses known, and one of the earliest domesticated plants known. It also runs parallel with the "Green Future" objectives that are becoming increasingly popular. Hemp requires little to no pesticides, no herbicides, controls erosion of the topsoil, and produces oxygen. Furthermore, hemp can be used to replace many potentially harmful products, such as tree paper (the processing of which uses bleaches and other toxic chemicals, and contributes to deforestation), cosmetics, and plastics, most of which are petroleum-based and do not decompose easily.
Licenses for hemp cultivation are issued in the European Union and Canada. In the United Kingdom, these licenses are issued by the Home Office under the Misuse of Drugs Act 1971. When grown for non-drug purposes hemp is referred to as industrial hemp, and a common product is fiber for use in a wide variety of products, as well as the seed for nutritional aspects as well as for the oil. Feral hemp or ditch weed is usually a naturalized fiber or oilseed strain of Cannabis that has escaped from cultivation and is self-seeding.
Cannabis sativa L. subsp. sativa var. sativa is the variety grown for industrial use in Europe, Canada, and elsewhere, while C. sativa subsp. indica generally has poor fiber quality and is primarily used for production of recreational and medicinal drugs. The major difference between the two types of plants is the appearance and the amount of Δ9-tetrahydrocannabinol (THC) secreted in a resinous mixture by epidermal hairs called glandular trichomes. Strains of Cannabis approved for industrial hemp production produce only minute amounts of this psychoactive drug, not enough for any physical or psychological effects. Typically, Hemp contains below 0.3% THC, while Cannabis grown for marijuana can contain anywhere from 6 or 7 % to 20% or even more.
Industrial Hemp is produced in many countries around the world. Major producers include Canada, France, and China. The United States is the only industrialized nation to continue to ban industrial hemp. While the Hemp is imported to the United States more than to any other country, the United States Government does not distinguish between marijuana and non-psychoactive Cannabis used for industrial and commercial purposes.
In Europe and China, hemp fibers are increasingly used to strengthen cement, and in other composite materials for many construction and manufacturing applications. Hempcrete is used as a construction material containing hemp hurds, especially in France. Mercedes-Benz uses a "biocomposite" composed principally of hemp fiber for the manufacture of interior panels in some of its automobiles.
Within the UK, the Department for Environment, Food and Rural Affairs (Defra) treats hemp as purely a non-food crop. Seed appears on the UK market as a legal food product although cultivation licenses are not available for this purpose. In North America, hemp seed food products are sold in small volumes, typically in health food stores or by mail order.
|Oleic 18:1 (Omega-9)||4|
|Linoleic 18:2 (Omega-6)||17|
|Linolenic 18:3 (Omega-3)||5|
|Linolenic 18:3 (Omega-6)||1|
|Vitamin A (B-Carotene)||37 IU|
|Thiamine (Vit B1)||1 mg|
|Riboflavin (Vit B2)||1 mg|
|Vitamin B6||0 mg|
|Niacin (Vit B3)||1 mg|
|Vitamin C||1.0 mg|
|Vitamin D||10 IU|
|Vitamin E||3 IU|
30–35% of the weight of hempseed is oil containing 80% essential fatty acids (EFAs), linoleic acid (LA, 50-70%), alpha-linolenic acid (ALA, 15–25%) and gamma-linolenic acid (GLA, 1–6%). The proportions of linoleic acid and alpha-linolenic acid in hempseed oil meet human requirements for EFAs. Unlike flax oil and others, hempseed oil can be used continuously without developing a deficiency or other imbalance of EFAs. Unfortunately the unsaturated fat makes the oil rancid quickly, unless it is stored in dark coloured bottles or mixed with chemical preservatives. This makes hemp oil difficult to transport or store. The high unsaturated fat content also makes the oil unsuitable for frying. This severely limits hemp oil's potential on the food market, although some marketing potential exists as a nutritional supplement.
Hemp seed also contains 20% complete and highly-digestible protein, 1/3 as edestin protein and 2/3 as albumins. Its high quality amino acid composition is closer to "complete" sources of proteins (meat, milk, eggs) than all other oil seeds except quinoa and soy.
Hemp seed oil has anti-inflammatory properties.
The fiber is one of the most valuable parts of the hemp plant. It is commonly called bast, which refers to the fibers that grow on the outside of the woody interior of the plant's stalk, and under the outer most part (the bark). Bast fibers give the plants strength, which is especially true with the hemp plant. Hemp fibers can be 0.91 m (3 ft.) to 4.6 m (15 ft.) long, running the length of the plant. Depending on the processing used to remove the fiber from the stem, the hemp may naturally be creamy white, brown, gray, black or green.
The use of hemp for fiber production has declined sharply over the last two centuries, but before the industrial revolution, hemp was a popular fiber because it is strong and grows quickly; it produces 250% more fiber than cotton and 600% more fiber than flax when grown on the same land. Hemp has been used to make paper. The Declaration of Independence was drafted by Jefferson on hemp paper. It was used to make canvas, and the word canvas derives from cannabis. Hemp was very popular as it had many uses. Manila replaced its use for rope. Burlap, made from jute, took over the sacking market. The paper industry began using wood pulp. The carpet industry switched over to wool, sisal, and jute, then nylon. Netting and webbing applications were taken over by cotton and synthetics. The world hemp paper pulp production was believed to be around 120,000 tons per year in 1991 which was about 0.05 % of the world's annual pulp production volume.
In 1916, US Department of Agriculture chief scientists Lyster H. Dewe, and Jason L. Merrill created paper made from hemp pulp, which they concluded was "favorable in comparison with those used with pulp wood. Jack Herer later summarized the findings of the bulletin in his book "The Emperor Wears No Clothes. Herer wrote:
New technology has allowed for more environmentally-friendly paper production from wood pulp. The recovery boiler was invented in the early 1930s. The first recovery boilers were commissioned to wood-pulp mills during the mid-1930s, ECF (Elemental Chlorine Free), or TCF (Total chlorine Free) bleaching, better fiber filters etc. has created less of a demand for alternative raw materials. Hemp is currently of little significance as raw material for paper; however, it is scarcely grown in the developed world. The long-term price for pulpwood has been low compared with any alternative except recycled paper. More about wood pulp technology in bleaching of wood pulp.
The decision of the United States Congress to pass the 1937 Marijuana Tax Act was based in part on testimony derived from articles in newspapers owned by William Randolph Hearst, who, some authors stress, had significant financial interests in the forest industry, which manufactured his newsprint. But the Hearst chain was also U.S. biggest buyer of newsprint. It therefore seems that it would have been in Hearst’s interest to promote cheap hemp paper substitutes, had that been a viable alternative.
The background material also included that from 1880 to 1933 the hemp grown in the United States had declined from 15,000 to , and that the price of line hemp had dropped from $12.50 per pound in 1914 to $9.00 per pound in 1933. In 1935, however, hemp would also make a significant rebound. Hearst began a campaign against hemp, and published stories in his newspapers associating hemp with marijuana and attacking marijuana usage. As a result of the act, the production and use of hemp was discontinued.
Characteristics of hemp fibre are its superior strength and durability, resistance to ultraviolet light and mold, comfort and good absorbency (8%). The original Levi Strauss jeans were made from lightweight hemp canvas. Hemp rope is notorious for breaking due to rot as the capillary effect of the rope-woven fibres tended to hold liquid at the interior, while seeming dry from the outside. Hemp rope used in the age of sailing-ships was protected by tarring, a labor-intensive process (and source of the Jack Tar nickname for sailors). Hemp rope was phased out when Manila, which does not require tarring, became available.
There is a niche market for hemp paper, but the cost of hemp pulp is approximately six times that of wood pulp, mostly due to the small size and outdated equipment of the few hemp processing plants in the Western world. Hemp pulp is bleached with hydrogen peroxide, which can also be used for wood pulp. Kenaf is another fast-growing plant which can be used as a replacement for wood pulp. Kenaf paper has been produced in commercial quantities.
A modest hemp industry exists. Recent developments in processing have made it possible to soften coarse fibres to a wearable level.
Hemp, because of its height, dense foliage and its high planting density as a crop, is a very effective and long used method of killing tough weeds in farming. Using hemp this way can help farmers avoid the use of herbicides, to help gain organic certification and to gain the benefits of crop rotation per se.
Biofuels such as biodiesel and alcohol fuel can be made from the oils in hemp seeds and stalks, and the fermentation of the plant as a whole, respectively. The energy from hemp may be high based on acreage or weight, but can be low based on the volume of the light weight harvested hemp. It does, however, produce more energy per acre per year than corn, sugar, flax, or any other crop currently grown for ethanol or biodiesel.
Henry Ford grew industrial hemp on his estate after 1937, possibly to prove the cheapness of methanol production at Iron Mountain. He made plastic cars with wheat straw, hemp and sisal. (Popular Mechanics, Dec. 1941, "Pinch Hitters for Defense.") In 1892, Rudolph Diesel invented the diesel engine, which he intended to fuel "by a variety of fuels, especially vegetable and seed oils.
Millennia of selective breeding have resulted in varieties that look quite different. Also, breeding since circa 1930 has focused quite specifically on producing strains which would perform very poorly as sources of drug material. Hemp grown for fibre is planted closely, resulting in tall, slender plants with long fibres. Ideally, according to Defra in 2004 the herb should be harvested before it flowers. This early cropping is done because fibre quality declines if flowering is allowed and, incidentally, this cropping also pre-empts the herb's maturity as a potential source of drug material. However, in these strains of industrial hemp the tetrahydrocannabinol (THC) content would have been very low regardless.
The name Cannabis is the genus and was the name favoured by the 19th century medical practitioners who helped to introduce the herb's drug potential to modern English-speaking consciousness. Cannabis for non-drug purposes (especially ropes and textiles) was then already well known as hemp.
The name "Marijuana" is Spanish in origin and associated almost exclusively with the herb's drug potential. That marijuana is now well known in English as a name for drug material is due largely to the efforts of US drug prohibitionists during the 1920s and 1930s.
From the 1881 Household Cyclopedia:
Smallholder plots are usually harvested by hand. The plants are cut at 2 to 3 cm above the soil and left on the ground to dry. Mechanical harvesting is now common, using specially adapted cutter-binders or simpler cutters.
The cut hemp is laid in swathes to dry for up to four days. This was traditionally followed by retting, either water retting (the bundled hemp floats in water) or dew retting (the hemp remains on the ground and is affected by the moisture in dew moisture, and by molds and bacterial action). Modern processes use steam and machinery to separate the fibre, a process known as thermo-mechanical pulping.
There are broadly three groups of Cannabis varieties being cultivated today:
A nominal if not legal distinction is often made between hemp, with concentrations of the psychoactive chemical THC far too low to be useful as a drug, and Cannabis used for medical, recreational, or spiritual purposes.
Hemp use dates back to the Stone Age, with hemp fibre imprints found in pottery shards in China and Taiwan over 10,000 years old. Legend credits Ts'ai-Lun, a Chinese eunuch in the emperor's court, with inventing paper about 105 AD. Specimens were found in the Great Wall of China which date back 200 years earlier. These papers were made from hemp. These ancient Asians also used the same fibres to make clothes, shoes, ropes, and an early form of paper.
Hemp cloth was more common than linen until the mid 14th century. The use of hemp as a cloth was centered largely in the countryside, with higher quality textiles being available in the towns. Virtually every small town had access to a hemp field.
The traditional European hemp was by tradition and due to its low narcotic effect not used as a drug in Europe. It was cultivated for its fibers and for example used by Christopher Columbus for ropes on his ships.
The Spaniards first brought hemp to the Western Hemisphere and cultivated it in Chile starting about 1545. As early as 1633, the Virginia House of Burgesses passed an act requiring all planters in Virginia to sow "hempe" (sic) on their plantations. The Puritans are first known to have cultivated hemp in New England in 1645.
George Washington and Thomas Jefferson both cultivated hemp on their farms—the Declaration of Independence was drafted on paper made from hemp fibers. Benjamin Franklin started the first American paper mill, which made paper exclusively from hemp.
In the Napoleonic era, many military uniforms were made of hemp. While hemp linens were coarser than those made of flax, the added strength and durability of hemp, as well as the lower cost, meant that hemp uniforms were preferred.
Hemp was used extensively by the United States during WWII. Uniforms, canvas, and rope were among the main textiles created from the hemp plant at this time. Much of the hemp used was planted in the Midwest and Kentucky. Historically, hemp production made up a significant portion of Kentucky's economy and many slave plantations located there focused on producing hemp.
By the early twentieth century, the advent of the steam engine and the diesel engine ended the reign of the sailing ship. The advent of iron and steel for cable and ships' hulls further eliminated natural fibers in marine use, although hemp had long since fallen out of favour in the sailing industry in preference to Manila hemp. The invention of artificial fibers in the late thirties by DuPont further put strain on the market.
More than 30 nations currently produce industrial hemp including Australia, Austria, Canada, China, England, France, Russia and Spain.
From the 1950s to the 1980s the Soviet Union was the world's largest producer (3,000 km² in 1970). The main production areas were in Ukraine, the Kursk and Orel regions of Russia, and near the Polish border. Since its inception in 1931, the Hemp Breeding Department at the Institute of Bast Crops (Научно-исследовательский институт лубяных культур) in Hlukhiv (Glukhov), Ukraine, has been one of the world's largest centers for developing new hemp varieties, focusing on improving fiber quality, per-hectare yields, and low THC content.
In Japan, hemp was historically used as paper and a fiber crop; it was restricted as a narcotic drug in 1948. The ban on marijuana imposed by the US authorities was alien to Japanese culture, as the drug had never been widely used in Japan before. There is archaeological evidence that cannabis was used for clothing and the seeds were eaten in Japan right back to the Jōmon period (10,000 to 300 BCE). Many Kimono designs portray hemp, or "Asa" (麻), as a beautiful plant.
France (8,000 hectares cultivated) is Europe's biggest producer. Canada (2,500 ha in 2004), the United Kingdom, and Germany all resumed commercial production in the 1990s. British production is mostly used as bedding for horses; other uses are under development. The largest outlet for German fibre is composite automotive panels. Companies in Canada, UK, US and Germany among many others process hemp seed into a growing range of food products and cosmetics; many traditional growing countries still continue to produce textile grade fibre.
Hemp is illegal to freely grow in the U.S. and several other countries because the plant is related to marijuana. In such countries, hemp is imported from China and the Philippines.
Hemp advocates foresee a bright future for hemp. As mentioned earlier, as a health food, hemp has become increasingly popular in America and abroad. Canada has been increasing its crop and exports, although Canada only grows hemp for seed and oil, not fiber. The real future for hemp remains under the surface, and prices remain too high for any significant consumer use.
Hemp laws are being passed around the United States in states such as Kentucky, Vermont and North Dakota. Pro-hemp laws have been passed in a dozen states, five in North Dakota (ND) alone. Under the new ND law, farmers no longer need permission from the DEA to grow industrial hemp, which now is distinguished from "marijuana". ND was very close to its first growing season, but the DEA delayed the applications too late to begin the season.
The bright future exists in the environmental merit of hemp. Hemp is sold alongside organic cotton for clothes and is becoming popular as environmental awareness becomes more prevalent. Hemp has been written about in newspapers and magazines across the country, though few people know about hemp and its various benefits and uses.
Hemp Plastic is a new technology based on 20-100% hemp fiber-based plastics that can be molded or injection molded. Demand for fiber-reinforced composites and other natural plastics could become more popular as oil prices rise and environmental awareness increases.
The increased demand for health food has stimulated the trade of shelled hemp seed, hemp protein powder and hemp oil as well as finished and ready-to-eat food products (waffles, granola bars, ice cream, and milk for example) using these derivatives as ingredients. The use of hemp oil in the manufacture of body care products has also increased.
Hemp contains delta-9-tetrahydrocannabinol (THC), which is the psychoactive ingredient found in hashish and marijuana. While THC is present in all Cannabis plant varieties to some extent, industrial hemp does not contain an amount to produce any intoxicating effect, even in significant quantities. In varieties grown for use as a drug, where males are removed in order to prevent fertilization, THC levels can reach as high as 24% in the unfertilized females which are given ample room to flower. In hemp varieties grown for seed or fibre use, the plants are grown very closely together and a very dense biomass product is obtained, rich in oil from the seeds and fibre from the stalks and low in THC content. EU and Canadian regulations limit THC content to 0.3% in industrial hemp.
On October 9, 2001, the US Drug Enforcement Administration (DEA) ruled that even traces of THC in products intended for food use would be illegal as of February 6, 2002. This Interpretive Rule would have ruled out the production or use of hempseed or hempseed oil in food use in the USA, but after the Hemp Industries Association (HIA) filed suit the rule was stayed by the United States Court of Appeals for the Ninth Circuit on March 7, 2002. On March 21, 2003, the DEA issued a nearly identical Final Rule which was also stayed by the Ninth Circuit Court of Appeals on April 16, 2003. On February 6, 2004, the Ninth Circuit Court of Appeals issued a unanimous decision in favor of the HIA in which Judge Betty Fletcher wrote, "[T]hey (DEA) cannot regulate naturally-occurring THC not contained within or derived from marijuana-i.e. non-psychoactive hemp is not included in Schedule I. The DEA has no authority to regulate drugs that are not scheduled, and it has not followed procedures required to schedule a substance. The DEA's definition of "THC" contravenes the unambiguously expressed intent of Congress in the Controlled Substances Act (CSA) and cannot be upheld." On September 28, 2004, the HIA claimed victory after DEA declined to appeal to the Supreme Court of the United States the ruling from the Ninth Circuit Court of Appeals protecting the sale of hemp-containing foods. Industrial hemp remains legal for import and sale in the U.S., but U.S. farmers still are not permitted to grow it.
Strong opposition to trace amounts of THC, a chemical shown by scientific research to be less harmful and less addictive than nicotine or alcohol, leads some of its critics, like Jack Herer in The Emperor Wears No Clothes, to charge ulterior motives such as protection of the synthetic-fibre, wood pulp, petrochemical, and pharmochemical industries. The US government's position has not been completely constant, as shown by the wide-spread cultivation of industrial hemp in Kentucky and Wisconsin during World War II. Critics of the HIA, however, argue that the necessities of the war and the unavailability of adequate synthetic substitutes outweighed the social, health, and public safety risks of producing hemp.
The presence of THC in hemp varieties and the fear that fields with hemp can hide cultivation of cannabis with more THC has hampered the development of hemp in many countries, most notably, the United States. Regulations in certain countries in EU demand approved variety of the seed and registration of the field in advance every year.
Marijuana is often female only, and kept completely isolated from any males, to keep the THC production up and seed production low. There are specially developed strains that require a very specific growing operation, and there is much care put into increasing THC production. Hiding marijuana in a hemp field would create a variety of problems. One is, the dense hemp would most likely "choke out" the marijuana, taking valuable and necessary nutrients and sunlight that the marijuana needs to produce THC. Even more, the male hemp plants would fertilize the marijuana plants, which would have several side effects. First, the marijuana would produce seeds, quickly lowering its value. Energy growing seeds quickly diminishes THC content. More importantly, the fertilization essentially crossbreeds the hemp and marijuana (only in the THC potent females). While the hemp will not produce any more THC, the marijuana, once "tainted" by the Hemp, will produce significantly less THC, depending on how long and how close the contact is with the Hemp.
If marijuana was successfully hidden and grown in a hemp field, the resulting plant matter would be of very little street value. It would be full of seeds and stems (because of fertilization), be malnourished (because hemp, like a strong weed, sucks up nutrients and grows taller, taking the available sun), and above all, have a very low THC content, making it undesirable to even the indiscriminate marijuana users. There is a consensus between experts and marijuana growers alike; the risk to reward ratio is too far out of proportion for it to even be considered.