On an annual basis, 1 acre of hemp will produce as much fibre as 2 to 3 acres of cotton. Hemp fibre is stronger and softer than cotton, lasts twice as long as cotton, and will not mildew.
Hemp use dates back to the Stone Age, with hemp fibre imprints found in pottery shards in China over 10,000 years old. Hemp is thought to be the first domestically-cultivated plant, with evidence of hemp fabric dating to 8,000 years ago found in Turkey (former-day Mesopotamia). Other evidence suggests cultivation further back by two or more thousands of years.
The word hemp has been used in the past to Europe to describe other fibre plants, including sisal and jute.
Beer hops (Humulus genus) are a close cousin of genus Cannabis, both of which fall under family Cannabaceae.
Hemp was not always treated as the same as marijuana by the U.S. government. The word “marihuana” (now marijuana) was coined in the 1890s, but not used until the 1930s by the U.S. Bureau of Narcotics (replaced by the DEA) to refer to all forms of cannabis.
According to the documentary “The Union: The Business Behind Getting High” (available at YouTube), the first marijuana law in the United States was enacted in 1619, in Jamestown Colony, Virginia, and actually required farmers to grow hemp.
Benjamin Franklin used hemp in his paper mill – one of the country’s first – and the first two copies of the Declaration of Independence were supposedly written on hemp paper.
In parts of the Americas, hemp was legal tender and could be used to pay taxes.
Hemp paper is stronger than wood-based paper, and can withstand more folding. In general, hemp has strongest natural fibre of any source.
Hemp paper hundreds of years old (found in museums) has not yellowed, and is thus a high quality paper of archival quality.
Hemp can grow nearly anywhere in the world, in many types of soil — even in short growing seasons or in dry regions — and helps purify soil as well as kills some types of weeds
Hemp can grow without pesticides. The crop also kills some weeds, purifies soil (bioregenerative), and is suitable for rotation use, due not only to its short harvest cycle (120 days).
Hemp is a high-yield crop. One acre of hemp produces twice as much oil as one acre of peanuts, and nearly four times as much fibre pulp (for paper) as an acre of trees.
Hemp paper is naturally acid-free and does not yellow as quickly as tree pulp-based paper.
Hemp has the strongest (and longest) plant fibre in the world, resistant to rot and abrasion, and was in long use before DuPont patented nylon in 1937. It was used for ship rigging, military uniforms, parachute webbing, baggage and more.
Because of its strength, hemp fibre can be used for composite materials that could be used to make anything from skateboard decks to car and stealth fighter bodies.
Car makers are using hemp in their cars, including Audi, BMW, Ford, GM, Chrysler, Honda, Iveco, Lotus, Mercedes, Mitsubishi, Porsche, Saturn, Volkswagen and Volvo. For example, the Mercedes C-Class contains up to 20 kg in each car.
A hemp composite material (with limestone and water) forms a type of concrete (hempcrete) that can be used for home building, at 1/9th the weight. It also acts as insulation and repels some vermin.
Levi jeans were originally made from hemp sailcloth (and rivets), for goldminers in California, who would fill their pockets with gold.
Henry Ford, founder of the Ford Motor Company, created a plastic car in 1941 which ran on hemp and other plant-based fuels, and whose fenders were made of hemp and other materials. Ford had a plan to “grow automobiles from the soil.” (Note: a company in France is experimenting with a similar vehicle in current day.)
Despite the active Marijuana Tax Act and the official federal government stance on hemp and marijuana, the U.S. Army and the Dept of Agriculture jointly produced a 1942 film, “Hemp for Victory,” encouraging farmers to grow hemp for the country’s effort in World War II — particularly for textiles and rope, imports of which had been cut off by war. Over 100,000 acres of hemp was growing in the U.S., but all related permits were cancelled when WW II ended.
Cotton grows only in moderate climates and requires more water than hemp; but hemp is frost tolerant, requires only moderate amounts of water, and grows in all 50 states. Cotton requires large quantities of pesticides and herbicides--50% of the world's pesticides/herbicides are used in the production of cotton. Hemp requires no pesticides, no herbicides, and only moderate amounts of fertiliser.
On an annual basis, 1 acre of hemp will produce as much paper as 2 to 4 acres of trees. From tissue paper to cardboard, all types of paper products can be produced from hemp.
The quality of hemp paper is superior to tree-based paper. Hemp paper will last hundreds of years without degrading, can be recycled many more times than tree-based paper, and requires less toxic chemicals in the manufacturing process than does paper made from trees.
Hemp can be used to produce fibreboard that is stronger and lighter than wood. Substituting hemp fibreboard for timber would further reduce the need to cut down our forests.
Hemp can be used to produce strong, durable and environmentally-friendly plastic substitutes. Thousands of products made from petroleum-based plastics can be produced from hemp-based composites.
It takes years for trees to grow until they can be harvested for paper or wood, but hemp is ready for harvesting only 120 days after it is planted. Hemp can grow on most land suitable for farming, while forests and tree farms require large tracts of land available in few locations. Harvesting hemp rather than trees would also eliminate erosion due to logging, thereby reducing topsoil loss and water pollution caused by soil runoff.
Hemp seeds contain a protein that is more nutritious and more economical to produce than soybean protein. Hemp seeds are not intoxicating. Hemp seed protein can be used to produce virtually any product made from soybean: tofu, veggie burgers, butter, cheese, salad oils, ice cream, milk, etc. Hemp seed can also be ground into a nutritious flour that can be used to produce baked goods such as pasta, cookies, and breads.
Hemp seed oil can be used to produce non-toxic diesel fuel, paint, varnish, detergent, ink and lubricating oil. Because hemp seeds account for up to half the weight of a mature hemp plant, hemp seed is a viable source for these products.
Just as corn can be converted into clean-burning ethanol fuel, so can hemp. Because hemp produces more biomass than any plant species (including corn) that can be grown in a wide range of climates and locations, hemp has great potential to become a major source of ethanol fuel.
Literally millions of wild hemp plants currently grow throughout the U.S. Wild hemp, like hemp grown for industrial use, has no drug properties because of its low THC content. U.S. marijuana laws prevent farmers from growing the same hemp plant that proliferates in nature by the millions.
From 1776 to 1937, hemp was a major American crop and textiles made from hemp were common. Yet, The American Textile Museum, The Smithsonian Institute, and most American history books contain no mention of hemp. The government's War on Drugs has created an atmosphere of self censorship where speaking of hemp in a positive manner is considered politically incorrect or taboo.
United States Presidents George Washington and Thomas Jefferson grew hemp, used products made from hemp, and praised the hemp plant in some of their writings.
No other natural resource offers the potential of hemp. Cannabis Hemp is capable of producing significant quantities of paper, textiles, building materials, food, medicine, paint, detergent, varnish, oil, ink, and fuel. Unlike other crops, hemp can grow in most climates and on most farmland throughout the world with moderate water and fertilizer requirements, no pesticides, and no herbicides. Cannabis Hemp (also known as Indian Hemp) has enormous potential to become a major natural resource that can benefit both the economy and the environment.
70% of the Cannabis Plant total weight is made up of the 'hurd' or woody inner core. This part of the plant is THC free (i.e. Hemp) and is used in housing construction. The silica leached from the soil by the plant combined with unslaked lime forms a chemical bond similar to cement which is fire and water proof. Cannabis Homes
Hemp may be grown also for food (the seed) but in the UK at least (and probably in other EU countries) cultivation licenses are not available for this purpose. Within Defra (the UK's Department for Environment, Food and Rural Affairs) hemp is treated as purely a non-food crop, despite the fact that seed can and does appear on the UK market as a perfectly legal food product.
Both the complete protein and the oils contained in hempseeds (rich in lanolin and linolenic acids) are in ideal ratios for human nutrition.
Until its rediscovery in the late 1980s, the use of hemp for fibre production had declined sharply over the past decades, but hemp still occupied an important place amongst natural fibres as it is strong, durable and unaffected by water. The main uses of hemp fibre were in rope, sacking, carpet, nets and webbing. A hemp clothing industry was reborn in the West in 1988, and hemp is being used in increasing quantities in paper manufacturing. The cellulose content is about 70%.
Harvesting the fibre
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 whereby the bundled hemp floats in water or dew retting whereby the hemp remains on the ground and is affected by the moisture in dew moisture, and by moulds and bacterial action. Modern processes use steam and machinery to separate the fibre, a process known as thermo-mechanical pulping.
Fuel can be a by-product of hemp cultivation. One fuel would be biodiesel because of the oils in the seeds and stalk of the hemp, another would be biofuel from the fibrous stalks.
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 fiber 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 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, even though the tetrahydrocannabinol (THC) content would still be very low with these strains of hemp.
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 Mexican (or Latin American) 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. We can surmise that this name was highlighted because it helped to characterize the herbal drug as quite alien to English-speaking culture.
There are broadly three groups of Cannabis varieties being cultivated today:
- Varieties primarily cultivated for their fibre, characterized by long stems and little branching, called industrial hemp
- Varieties grown for seed from which hemp oil is extracted
- Varieties grown for medicinal or adult use.
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.
Major hemp producing countries
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.
Other important producing countries were China, Hungary, the former Yugoslavia, Romania, Poland, France and Italy.
Canada, 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, USA and Germany among many others are processing hemp seed into a growing range of food products and cosmetics; many traditional growing countries still continue with textile grade fibre production.
Future of hemp
In the last decade hemp has been widely promoted as a crop for the future. This is stimulated by new technologies which make hemp suitable for industrial paper manufacturing, use as a renewable energy source (biofuel), and the use of hemp derivatives as replacement for petrochemical products.
The increased demand for health food has stimulated the trade in shelled hemp seed. Hemp oil is increasingly being used in the manufacturing of bodycare products.
THC in hemp
Hemp contains delta-9-tetrahydrocannabinol (THC), which is the psychoactive ingredient found in hashish. THC is present in all hemp varieties to some extent. In varieties grown for use as a drug, where males are removed in order to prevent fertilization, THC levels can reach as high as 20-30% 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 regulations limit THC content to 0.3% in industrial hemp. In Canada, the THC limit is 1%
The presence of (some) THC in hemp varieties and the fear that THC could be extracted from industrial hemp for illegal purposes has hampered the development of hemp in many countries. Since the early 1990s, however, many countries, including Canada, Australia, the UK, The Netherlands and Germany, allow hemp plantings and commercial scale production. Plant breeders are working on the development of new varieties which are low in THC.