Hemp

Resources

Hemp, or Cannabis sativa, is a tall, annual plant that thrives in temperate and subtropical climates. It is native to central and western Asia, and is one of the oldest cultivated plants. The word “hemp” is derived from the old English word “henep,” and refers to both the plant and the long fibers that are processed from its stems. The most common use of hemp has been as a source of fiber for manufacturing rope, canvas, other textiles, and paper. Hemp is also the source of marijuana, a psychoactive drug banned in most countries. It contains more than 400 biochemicals, and has been used for medicinal purposes for at least 3,000 years.

Even today, it is useful as a treatment for cancer and AIDS patients, because its stimulatory effect on the appetite can help victims of these diseases to avoid weight loss.

Hemp is a dioecious plant, meaning there are separate male and female plants. It is an annual herbaceous plant that can grow as tall as 10-20 feet (3-6 m). Hemp can be cultivated in a wide range of climates that have adequate amounts of sun and moisture during the summer. Hemp has a relatively short growing season, and, in the Northern Hemisphere, is planted in May and harvested in September. As hemp grows it improves soil quality somewhat, and reduces the abundance of weeds by casting a dense shade over the ground surface.

Hemp has been grown for at least 5,000 years to obtain its stem fibers for weaving cordage and textiles. Its fibers can be used to make rope, canvas, and other materials. Its seeds can be pressed for oil, which is used in paint, heating and lubricating oils, animal feed, and pharmaceutical products. The plant also produces a sap rich in silica, which can be used for making abrasives.

For centuries, hemp was the largest cash crop in the world. As recently as 1941, farmers in the United States were encouraged by the federal government to grow hemp, because of the need for its fibers to make rope, parachutes, backpacks, hoses, and other necessities during World War II (1939–1945).

The cultivation of hemp has been outlawed in the United States and many other countries because its flowering buds, and to a lesser degree its foliage, are the source of the drug marijuana. The buds produce a yellow resin that contains various cannabinoid chemicals. Of these, delta-9-tetrahydrocannabinol, or THC, has the most psychoactive activity. THC combines with receptor sites in the human brain to cause drowsiness, increased appetite, giddiness, hallucinations, and other psychoactive effects. Although the causative mechanisms are not fully understood, current research indicates that THC ingestion results in THC binding to receptor sites associated with measurable memory loss. Other studies correlate THC binding to receptors in the cerebellum and correlated decreases in motor coordination and/or the ability to maintain balance.

Plant breeders have now produced varieties of hemp with concentrations of THC that are too low for the plants to be used as a medicine or recreational drug. In Canada and many other countries, permits are being granted to allow farmers to grow low-THC hemp as a source of valuable fiber. Although United States federal law prohibits hemp growth, as of 2002 eight states had passed state legislation authorizing industrial hemp research.

In 2002 a United States federal appeals court blocked a Drug Enforcement Administration (DEA) rule that attempted to ban food and personal products made from hemp. Prior to the ruling the DEA—relying on the Controlled Substances Act—banned food products containing tetrahydrocannabinol (THC). After the DEA was denied a reahearing by the court in 2004, the agency declined to take the case to the Supreme Court, handing a victory to the hemp industry.

See also Natural fibers.

Resources

BOOKS

Bosca, I. and M. Karus. The Cultivation of Hemp: Botany, Varieties, Cultivation, and Harvesting. Hemptech Pub., 1998.

OTHER

New Standard. “U.S. Hemp Industry Wins Battle with DEA” <http://newstandardnews.net/content/index.cfm/items/1485> (accessed November 28, 2006).

HEMP

Hemp is a soft bast fiber from the stem of a plant, as are flax, jute, and ramie. Hemp plant fibers are three to twelve feet long and are made up of bundled cellular fibers. The plant itself, Cannabis sativa, is hardy and can be grown in most locations and climates around the world and requires moderate water. Its recorded use for food, shelter, and fiber dates from at least to 8000 b.c.e. Although ethno botanists and others cannot be absolutely sure, it is thought that hemp was first grown in Asia.

Hemp can be fabricated for clothing, canvas, rope, and other uses. While hemp is not as soft as cotton, it is stronger than other cellulosics, such as flax, and more absorbent than cotton. Due to hemp's coarse and tough attributes it must be retted (rotted), a process by which the fibers are broken down microbially or chemically, decomposing the pectins that attach the bast fibers to the woody inner part of the stem known as the hurd or shive. Natural retting can be accomplished by simply allowing the cut stems to lie in damp fields for several weeks or by placing the stems in running water. The process of separating the bast fibers from the hurd is extremely difficult even when mechanized. The hurd is cleaned from the fiber by scutching (beating) and the fiber is further refined by hackling (combing). Thus, the retting, separating, and cleaning processes are lengthy and, therefore, expensive compared with other natural fibers. Overall, the production and processing of hemp is prohibitively expensive for routine consumer products.

Because hemp is naturally resistant to ultraviolet light, mold, and mildew, and to salt water, it has been used extensively for centuries by ships for sail canvas and rope. Farmers in the United States were encouraged to grow industrial hemp when, during World War II, the United States was denied access to abaca (called Manila hemp) from the Philippines. The U.S. Department of Agriculture produced a film titled "Hemp for Victory" and subsidized hemp cultivation by farmers. After World War II, industrial hemp cultivation was outlawed due to its association with marijuana hemp, a different variety of Cannabis sativa. In 1999, Hawaii became the first state since 1957 in the United States to plant hemp seeds legally. Hawaii's hemp project ended on 30 September 2003, when the Drug Enforcement Agency (DEA) ended Hawaii's attempt to grow industrial hemp. Industrial hemp is harvested in Canada, China, and most of Europe.

Hemp was reputedly used by Levi Strauss for the first Levi trousers sent to miners during the U.S. gold rush in the mid-1800s. Hemp fibers and yarns can be successfully combined with other natural fibers and yarns, including silk, and with synthetic fibers and yarns. Processed hemp is imported into the United States for use in industrial carpeting and upholstery as well as light supple dress weights.

In 2003, there were several businesses in the United States selling hemp fabrics or hemp blend fabrics for various uses. There were a large number of retailers who sold hemp and hemp blend products ranging from knitted T-shirts to woven and printed aloha shirts. Hemp fabrics become softer with repeated use and washing. Home products and accessories such as upholstery and table linens made from hemp are found to have strong market appeal to those seeking natural textile products. At the turn of the twenty-first century, consumer use of hemp fabrics could be seen as a novelty touched by hemp's arcane association with forbidden marijuana.

See alsoHawaiian Shirt; Levi Strauss .

bibliography

Barber, E. J. W. Prehistoric Textiles. Princeton, N.J.: Princeton University Press, 1991.

Blair, C. "Hemp Dies in Hawaii." Honolulu Weekly, 8 October 2003.

Kadolph, Sara J., and Anna L Langford. Textiles. 8th ed. Upper Saddle River, N.J.: Prentice-Hall, 1998.

Zimmerman, Malia. "Some See Profit in Hawaii Hemp." Pacific Business News, 9 July 1999.

Carol Anne Dickson

Hemp

Hemp, or Cannabis sativa, is a tall, annual plant that thrives in temperate and subtropical climates. It is native to central and western Asia , and is one of the oldest cultivated plants. The word "hemp" is derived from the old English word "hanf," and refers to both the plant and the long fibers that are processed from its stems. The most common use of hemp has been as a source of fiber for manufacturing rope, canvas, other textiles , and paper . Hemp contains more than 400 biochemicals, and has been used for medicinal purposes for at least 3,000 years. Even today, it is useful as a treatment for cancer and AIDS patients, because its stimulatory effect on the appetite can help victims of these diseases to avoid weight loss. During the twentieth century hemp gained notoriety as the source of marijuana , a psychoactive drug banned in most countries.

Hemp is a dioecious plant, meaning there are separate male and female plants. It is an annual, herbaceous plant that can grow as tall as 10–20 ft (3–6 m). Hemp can be cultivated in a wide range of climates having adequate amounts of sun and moisture during the summer. It has a relatively short growing season, and, in the Northern Hemisphere, is planted in May and harvested in September. As hemp grows it improves soil quality somewhat, and reduces the abundance of weeds by casting a dense shade over the ground surface.

Hemp has been grown for at least 5,000 years to obtain its stem fibers for weaving cordage and textiles. Its fibers can be used for manufacturing rope, canvas, and other materials. Its seeds can be pressed for oil, which is used for making paint, heating and lubricating oils, animal feed, and pharmaceutical products. The plant also produces a sap rich in silica, which can be used for making abrasives .

For centuries, hemp was the largest cash crop in the world. As recently as 1941, U.S. farmers were encouraged by the federal government to grow hemp, because of the need for its fibers to make rope, parachutes, backpacks, hoses, and other necessities during World War II.

The cultivation of hemp has been outlawed in the United States and many other countries because its flowering buds, and to a lesser degree its foliage, are the source of the drug marijuana. The buds produce a yellow resin that contains various cannabinoid chemicals. Of these, delta-9-tetrahydrocannabinol, or THC, has the most psychoactive activity. THC combines with receptor sites in the human brain to cause drowsiness, increased appetite, giddiness, hallucinations, and other psychoactive effects. Although the causative mechanisms are not fully known, current research indicates that THC ingestion results in THC binding to receptor sites associated with measurable memory loss. Other studies correlate THC binding to receptors in the cerebellum and correlated decreases in motor coordination and/or the ability to maintain balance.

Plant breeders have now produced varieties of hemp with concentrations of THC that are too low for the plants to be used as a medicine or recreational drug. In Canada and many other countries, permits are being granted to allow farmers to grow low-THC hemp as a source of valuable fiber. Although United States Federal law prohibits hemp growth, as of 2002 eight states had passed state legislation authorizing industrial hemp research.

In 2002, a United States federal appeals court blocked a Drug Enforcement Administration (DEA) rule that attempted to ban food made with hemp. Prior to the ruling the DEA—relying on the Controlled Substances Act—banned food products containing tetrahydrocannabinol (THC). At press, an appeal was pending.

See also Natural fibers.

Resources

books

Bosca, I., and M. Karus. The Cultivation of Hemp: Botany, Varieties, Cultivation, and Harvesting. Hemptech Pub., 1998.

HEMP

HEMP. Although England sought hemp from its American colonies to rig its sailing ships, and although the British government and colonial legislatures tried to encourage its production by bounties, it never became an important export crop. But the virgin clearings and moderate climate of America did invite its small-scale cultivation. Many colonial homesteads had hemp patches—hemp and tow cloth were familiar household manufactures, and local cordage supplied colonial shipyards.

After the American Revolution, when settlers began developing the rich Ohio Valley bottomlands, hemp became a staple crop in Kentucky. Lexington erected mills for manufacturing it, and Southwesterners used hemp cordage and bale cloth to pack their cotton crops. Output peaked around 1860 at about 74,000 tons, of which Kentucky produced 40,000 tons and Missouri 20,000 tons. Thereafter, the advent of the steamship, the substitution of steel for hemp cordage, and the introduction of artificial fibers lessened demand. American production of hemp for fiber ceased shortly after World War II.

With some twenty-five thousand uses, industrial hemp has undergone a revival in many countries such as France and Canada. The United States, however, continues to ban commercial hemp production because of fears by the Drug Enforcement Agency that the plant, which belongs to the same species as marijuana, would be put to illicit use. Agricultural advocacy groups have protested the DEA policy, pointing out that the THC content of hemp is so low that it would be useless as a drug and that the prohibition places American farmers at competitive disadvantage, depriving them of the income from a highly useful and potentially lucrative crop.

BIBLIOGRAPHY

Hopkins, James F. A History of the Hemp Industry in Kentucky. Lexington: University of Kentucky Press, 1951.

Nader, Ralph. "Farm Aid: The DEA Should Get Out of Regulating Hemp Agriculture." San Francisco Bay Guardian, April 3, 2000. Available at http://www.sfbg.com/nader/95.html.

Victor S.Clark/c. w.

See alsoBounties, Commercial ; Narcotics Trade and Legislation ; Shipping, Ocean .

hemp / hemp/ • n. (also Indian hemp) the cannabis plant, esp. when grown for fiber. ∎  the fiber of this plant, extracted from the stem and used to make rope, stout fabrics, fiberboard, and paper. ∎  used in names of other plants that yield fiber, e.g., Manila hemp. ∎  marijuana.ORIGIN: Old English henep, hænep, of Germanic origin; related to Dutch hennep and German Hanf, also to Greek kannabis.