With new concerns about soy foods emerging daily–from soy oil used for partially hydrogenated margarines and shortenings to soy protein used for baby formula and substitute foods–and with soybean prices declining, farmers are seeking new cash crops. Hemp and kenaf have emerged as good candidates to fill the void. Both crops provide fibrous material that can be used for a variety of industrial purposes, such as paper, rope, cloth and construction materials.
Hemp (Cannabis sativa),one of our oldest and most versatile plants, was first domesticated by the Chinese. Documentation of its use dates back as far as 2800 BC. The Chinese used hemp fiber, separated from the stalks, to make paper and rope. In 450 BC, the Greek historian Herodotus reported that hemp could be used to make fine cloth. In Europe, hemp fiber was used to make coarse fabrics and rope for sailing ships. When the art of papermaking arrived in Europe from China in the 14th century, rags of hemp and flax became the material of choice used for paper manufacture.
The American colonists relied heavily on hemp. At that time, hemp was the world’s leading crop. A law enacted in Virginia in 1619 made hemp production mandatory for all farmers. Similar laws were passed in Massachusetts in 1631, in Connecticut in 1632 and the Chesapeake Colonies in the mid 1700s. George Washington and Thomas Jefferson both farmed hemp. “Make the most you can of the hemp seed and grow it everywhere,” wrote George Washington in 1794. The first drafts of the Declaration of Independence were written on hemp paper and all early American flags were made with hemp. During the American Revolution, wives and daughters sewed hemp linens for the Continental Army and rope made from hemp was used to rig the early American Navy and Merchant Marine ships.
A Sorry History
So why is hemp not grown in America today? Why has the American creative genius not found ways to process hemp efficiently and turn it into a myriad of useful products, at least on a large scale?
The reason is twofold: Hemp competes directly with wood products and hemp belongs to the same plant family as marijuana. The history of how hemp products were removed from the American commercial scene deserves retelling, but only after this important disclaimer: This article is not intended to endorse the legalization of marijuana or the recreational use of this drug in any way.
Until the machine age, processing of hemp was a difficult and time-consuming business. Mature hemp is cut down and allowed to lie in the fields until all the leaves fall off. Then the fibrous outer portion of the stalk–called the bast–must be separated from the inner portion–called the hurds, a process that involved backbreaking labor.
New technologies in the early 1900s brought many industries into conflict. The DuPont Chemical Company developed a chemical process for turning wood pulp into paper. The procedure required bleaches and acids to whiten the tannin-stained wood fibers. DuPont also developed ways of making plastics from oil.
In the 1930s, a mechanical process was developed for decorticating hemp and making it into paper. Thus, hemp became a practical paper source, said to cost less than half that of paper made from tree pulp. Hemp also competed with the petroleum-based plastics industry since many plastic products could be made from hemp.
When the chemical paper pulping process was invented, DuPont entered into a multimillion dollar deal with a timber holding company and a newspaper chain owned by William Randolph Hearst, a deal that provided Hearst with a source of very cheap paper for his newspaper, not to mention profits from his timber interests. The chemically washed paper turned yellow as it got older which is why the Hearst style of sensational reporting acquired the term “yellow journalism.” Hearst knew that he could drive other newspapers out of business with the advantage that cheap newsprint gave him but the advent of even cheaper paper made from hemp threatened his plan.
To prevent unwanted competition from hemp products, Hearst engineered a misinformation campaign in his nationwide chain of newspapers. It was Hearst who popularized the Mexican slang term “marijuana” for hemp. Throughout the 1920s and 1930s, his papers stressed the evils of marijuana in lurid terms, but never pointed out that marijuana came from the same useful plant family as hemp and that it was impossible to get high by smoking hemp leaves.
In 1937, a DuPont ally on the House Ways and Means Committee introduced the Marijuana Tax Act Bill. It was prepared in secret and quickly presented for vote. The AMA did not realize until too late that marijuana, the plant Congress intended to outlaw, was actually cannabis, which at the time was an important part of the medicinal pharmacopeia. The AMA found out about the bill only two days before the hearings and sent a representative to object to the banning of cannabis medicines. A hemp bird seed sales man also showed up and complained.
There was little protest against the bill because Americans, even if they had known it existed, did not understand that cannabis hemp and marijuana were not the same thing. To add to the confusion, the word “hemp” is often wrongly used to refer to other natural fibers, such as jute.
Andrew Mellon of the Mellon Bank of Pittsburgh, DuPont’s chief financial backer, also played a role in the removal of hemp from the marketplace. As Secretary of the Treasury under Herbert Hoover, Mellon appointed the husband of his niece, Harry J. Anslinger, to head the Federal Bureau of Narcotics and Dangerous Drugs in 1931. After the Marijuana Tax Act passed, Anslinger’s agency enforced it with a vengeance for the next 30 years. The act made no chemical distinction between hemp and marijuana. The smokeable parts–the leaves and the flowers–were taxed at $100 per ounce. Instead of targeting marijuana coming in from Mexico, the Federal Bureau of Narcotics hassled Midwestern farmers with red tape and busting them if they found any leaves remaining on the stalks.
Anslinger’s office also prosecuted over 3,000 AMA doctors for illegal prescriptions until the AMA stopped fighting for the medicinal use of cannabis in 1939. Initially the pharmaceutical companies had also fought attempts to outlaw cannabis because it supplied so many important ingredients in pills and potions. Today, drug companies actually benefit from the ban as many are working to develop cannabis analogs that can be patented and sold at greater profit than unpatentable compounds from a common plant.
When Japan seized the Philippines in 1942, America’s supply of “Manila hemp” was cut off. This was not true cannabis hemp, but it was an excellent fiber for rope, boots, uniforms and parachute cording. The government then did an about-face and encouraged Americans farmers to be patriotic and grow hemp. Hemp was no longer called marijuana except on the permits issued to farmers, which referred to them as “Producers of Marijuana.” The Department of Agriculture even made a promotional film entitled Hemp for Victory. Some 400,000 acres of hemp were planted and the fibers were processed in 42 hemp mills built by the War Hemp Industries Corporation.
But after the war, hemp production was again discouraged. Americans were enamored of synthetic fabrics and no one clamored for natural fibers. The last hemp field was planted in Wisconsin in 1957. During the 1970s, all mention of hemp was removed from high school texts books in the United States.
Hemp & Marijuana: Not the Same Thing
The compound responsible for the psychoactive properties of marijuana is tetrahydrocannabinol or THC. Marijuana plants contain levels of THC ranging from 3 to 15 percent while plants grown for industrial hemp contain less than 1percent of THC. Cannabis grown for hemp also contains cannabidiol or CBD which blocks the effects of THC on the nervous system. According to researchers, low THC levels and high CBD levels in hemp plants negate any psychoactive effects. If hemp were psychoactive, there would be a tradition of smoking it. Farm lads have resorted to smoking corn silk to get high, but not to hemp leaves. In fact, those who have tried to do so report that hemp-smoking causes a headache, nothing more.
The Drug Enforcement Agency charges that enforcement agents can’t tell the difference between marijuana and hemp. But enforcement officers in 29 other countries, where marijuana is illegal and hemp is not, have no trouble telling the difference. Hemp, grown for stalks, is tall and spindly while marijuana, grown for flowers, is short and bushy. Officials claim that pot will be hidden in hemp fields, but marijuana cannot be grown with hemp because hemp produces a deep shade that chokes out even hardy weeds. In fact, the two crops must be cultivated at least seven miles apart because hemp pollen will render the next generation of marijuana less potent.
The poppy furnishes an example of a crop with both legal and illegal uses. Poppies grown for opium are illicit, but poppies grown for seed are legal and allowed in the food supply.
Hemp from earlier days of cultivation now grows as weeds, called ditchweed, which provides shelter and food for birds, as well as a repository for hemp seeds. Much of the government’s anti-marijuana efforts are directed at destroying ditchweed that grows throughout the Midwest. Given the history of the anti-hemp movement, advocates for legalization of hemp may be justified in asking whether there is a hidden agenda behind these well-publicized ditchweed fires.
Plant of Many Uses
Many different products can be made from hemp, all of which are biodegradable.
Cloth made from hemp is very durable. It was used to make canvas–a word derived from cannabis–cloth tough enough for sails, The first Levi’s blue jeans were made of hemp because if its durability. Hemp cloth is not as soft as cotton, but tougher and less likely to stretch.
Hemp advocates point out that hemp is a better crop for the environment than cotton, especially the way cotton is grown today. In the US, the cotton crop uses half the total pesticides. Cotton also needs a lot of fertilizer and, before harvest, is treated with a defoliant to remove all the leaves so that picking is easier. Today’s versatile and wearable cotton fabrics are the result of decades of fabric research. The same efforts applied to hemp can be expected to result in a wide range of natural fabrics that could rival cotton for many applications.
Hemp is also a perfect candidate for biomass fuel. The stalks can be burned as is or processed into charcoal, methanol, methane or ethanol. The charcoal may be burned in today’s coal-powered electric generators. Biomass fuels are clean and virtually free from metals and sulfur, so they don’t cause as much air pollution as fossil fuels. New types of generators, including ones small enough for home use, have been developed to use these biomass fuels. These development programs are geared to Third World countries that can’t afford the installation of expensive electricity infrastructure and that need local and affordable sources of power; but there are many potential applications in the United States as well.
One of the newest uses of hemp is for construction materials. It can be used in the manufacture of press board or composite board. This involves gluing fibrous hemp stalks together under pressure to produce a board that is many times more elastic and durable than hardwood. Because hemp produces a long tough fiber, it is the perfect source for press board. In addition, many plastics can be made from the high-cellulose hemp hurd.
French scientists have developed a process that uses hemp stalks to make a long-lasting cement. The process involves no synthetic chemicals and produces a material that works as a filler in building construction. Called Isochanvre, it can be used as drywall. It insulates against heat and noise and is very long lasting.
Plastic made from plants is not a new idea. Back in the 1930s, Henry Ford had already made a whole car body out of bioplastics. But processing for petroleum-based plastics was developed more quickly. The processes for making bioplastics require more research and development compared to those already in place for making plastics from fossil fuels.
Hemp oil can be used for cosmetics, paints, varnishes and inks. When combined with methanol, a substitute for diesel fuel is produced that burns 70 percent cleaner than diesel fuel made from petroleum.
There is also research into the use of hemp for bioremediation. Some plants break down or degrade organic pollutants and stabilize metal contaminants by acting as filters or traps. In 1998, researchers in Ukraine conducted field trials to improve phyto-extraction of lead, uranium, cesium-137 and strontium-90 from soils near the Chernoble nuclear reactor. Hemp turned out to be one of the best phyto-remediative plants tested.
Hemp for Paper?
The great debate concerns whether hemp can replace wood for paper manufacture. Advocates say that since 1937, about half the forests in the world have been cut down to make paper. Forestry representatives argue that today most paper comes from renewable forests. Environmentalists point out that making paper from wood requires many toxic chemicals; forestry interests argue that paper from hemp can never be economical.
Indeed, the future of hemp as an important cash crop will be largely dependent on whether economical hemp paper production can be achieved. A 1916 US Agriculture bulletin said that one acre of hemp produces as much cellulose fiber pulp as 4.1 acres of trees. A 1997 Forest Service report from Wisconsin, which was never issued, stated that hemp could supply the state’s entire demand for chlorine-bleached wood-based writing paper. The American Forest and Paper Association disputes these estimates, stating that high yield plants in Italy have produced 1.17 tons of paper-quality hemp fiber per acre, compared to American pine plantations that product two tons per acre.
Originally, only the fibrous outer bast was used in paper making. Until the 1930s, the hurds were normally considered a waste product and were thrown away after they were stripped of the bast. New research showed that these hurds could be used instead of wood in mechanical pulping, which would dramatically reduce the cost of making paper from hemp. In fact, in an article published early in 1938, Popular Mechanics Magazine predicted that hemp would rise to become the number one cash crop in America. The 1937 Marijuana Tax Act was so unexpected that Popular Mechanics had already gone to press with their cover story about hemp. It was published in 1938, just two months after the Tax Act took effect.
Critics of hemp for paper, such as US forest interests, usually only mention the fibrous bast for paper making. The bast comprises only about 25% of the stalk. It is uniquely suited to certain specialty types of paper, including stationary and acid-free paper for archival material. Today, however, lower cost papers such as newsprint can be made from the entire hemp stalk, which makes hemp yields comparable to those of wood and makes it a candidate for everyday paper uses.
Nevertheless, hurdles remain. New types of equipment are needed and, because hemp is difficult to store and transport, paper mills must necessarily be small scale and locally situated. This, in turn, makes financing for research and plant construction difficult to obtain. Hemp paper has a long way to go before it is commercially viable. When we enquired about printing Wise Traditions on hemp paper, we learned that it would increase the cost by about $1500 per issue.
A Miracle Plant?
Hemp seems like a good idea for farmers. It reaches maturity in 100 days without the need for pesticides. In can be grown in many climates and under many conditions. Its mature strength makes it impervious to storms. It produces dense shade that chokes out weeds. In fact, use of hemp as a rotation crop is a good way to get rid of weeds without herbicides. In England and Hungary, hemp grown in rotation with wheat increased the wheat harvest 20 percent.
Because hemp needs so few herbicides, pesticides, fungicides and fertilizers, it is very attractive to our debt-laden farmers. Hemp farmers in Canada make $250 an acre. One study showed that a crop of hemp in the US could return $319 per acre, compared with $135 for white corn. A Kentucky State government report estimated that high fiber hemp would bring net returns of $500 per acre to Kentucky farmers, compared to $175 for a wheat and soybean rotation, and surpassed only by processing tomatoes at $775 per acre.
European hemp production has yet to prove economical but in Canada, Hemp has become an important cash crop since it was legalized several years ago. The challenge to farm economies is creating a market for widescale production. America currently imports $120 million of hemp products. Further research, processing plant construction and marketing efforts will be needed to make significant inroads on the competition–wood and petroleum products. State governments, rather than the federal government, will mostly like provide the seed money for further development. The Europeans have already done considerable research.
Over half the states in the Union are considering laws to encourage hemp production and processing. In 1999, cultivation of hemp was legalized in Hawaii, North Dakota and Minnesota. In May of 2000, Maryland joined the list. In Virginia, lawmakers passed a resolution last year urging federal officials to “revise the necessary regulations” to permit hemp production there.
Environmental concerns, soaring demand for paper and falling prices for farm commodities will all spur further interest in hemp. Hemp is not yet the miracle crop described by enthusiasts but continued investment, research and lobbying efforts may soon make it one.
1. Jack Herer, Hemp & Marijuana: The Emperor Wears No Clothes. Published by HEMP, 5632 Van Nuys Boulevard, Suite 310, Van Nuys, CA 91401.
2. Brian S. Julin, “Frequently Asked Questions about Cannabis Hemp,” UMACRC, SAO Mailbox #2, Student Union Building, UMASS 01003, firstname.lastname@example.org.
3. David P West, PhD, “Hemp and Marijuana: Myths & Realities,” North American Industrial Hemp Council, PO Box 259329, Madison, WI 53725
Hemp: Not For Human Consumption
A number of companies are now selling hemp oil, toasted and shelled hemp seeds and granola bars containing hemp seeds. This is not a good use for hemp. Hemp may be appropriate for domestic animals and birds, but it should not be used for human food. In China, where cultivation of hemp originated, hemp oil was used occasionally, but there are no references in the Chinese literature to the use of hemp seeds as food for human beings. (Simoons, Food in China, 1991)
Hemp oil has been promoted in recent years as a “heart healthy” oil that is rich in essential fatty acids and low in saturated fat. Hemp oil is indeed highly unsaturated, and this is exactly why it should be avoided. Hemp oil is over 75 percent polyunsaturated, containing about 55 percent omega-6 fatty acids and about 20% omega-3 fatty acids. It contains only about 10 percent saturated fatty acids and 10 percent monounsaturated fatty acids. It is, therefore, highly unstable and prone to oxidation; and the high content of linoleic acid makes it particularly unsuitable for human consumption. Diets containing an excess of polyunsaturated fatty acids, particularly omega-6 fatty acids, have been linked not only to heart disease but also to cancer and autoimmune disease.
An additional problem derives from the fact that hemp oil may contain traces of cannabinoids and these substances can then turn up in the urine of those who consume it. In one research project, seven adult volunteers purchased hemp oil from a health food store and ingested 15 milliliters each. Urine samples taken at 8, 24 and 48 hours after ingestion were positive for THC. (Journal of Analytical Toxicology October 1997 21(6):482-485.) If these volunteers had been obliged to give a urine sample to their employers, they would have failed their drug test.
Because hemp oil is highly unsaturated, it makes an excellent base for paints and varnishes. In fact, there is no need to consider hemp for human consumption except in small quantities for medicinal purposes. There are many good fats and oils that humans can use and there are many good industrial uses for all the by-products of the hemp plant. Let’s not make the same mistake with hemp that we have made with soy, by promoting its inappropriate use as a human food.
Medical Uses for Cannabis
Since ancient times, a large number of medicines have been derived from the sticky resin in the leaves and blossoms of the hemp plant. Cannabis appears in almost every known book of medicine written by ancient scholars and was used as a treatment for headaches, asthma, pain, depression and epilepsy. In Chinese medicine, hemp seeds are used to treat some types of constipation.
In the US, cannabis extract was available as a medicine and legally sold until 1937, principally as a nerve tonic. There are over 60 chemicals in cannabis that may have medicinal uses. One chemical, cannabinol, may be useful as a sleeping medicine. Another, taken from premature buds, is called cannabidiolic acid. It is a powerful disinfectant. Cannabis dissolved in rubbing alcohol is effective against herpes sores and a salve made from cannabis one of its earliest medical uses. The leaves were once used in bandages. An herbal tea, said to be non-psychoactive, can be made from small cannabis stems. Today the psychoactive marijuana leaves are used to control nausea and vomiting in AIDS patients. Marijuana is also said to offer promise as a treatment for glaucoma and multiple sclerosis.
Kenaf (rhymes with giraffe) is a fiber-producing plant, Hibiscus cannabinus L, similar in appearance to hemp but of a different family. It thrives in hot damp climates. Originally from Africa, kenaf has been the subject of several studies by the Department of Agriculture and is now cultivated in several southern states. Kenaf grows quickly, rising to 12 to 18 feet within six months. Its yield is said to be five to ten tons of dry fiber per acre, or three to five times more than the yield obtained from Southern pine trees, which can take seven to 40 years to reach harvestable size. Kenaf is well suited to areas that currently grow cotton but needs much lower amounts of pesticides. It is resistant to the effects of both hurricanes and drought. Kenaf does not carry the marijuana stigma associated with hemp but, unfortunately, does not grow in colder climates.
In Africa, kenaf is used as a forage for animals. The bast fiber is used for cordage, the stalks are burned for fuel and the leaves are consumed as a vegetable. Until recently, production and processing has been a very labor-intensive process, but research and development in the US has resulted in completely mechanized methods for harvesting and processing.
Like hemp, kenaf can be processed into rope, paper and building materials such as fiber board and insulation. Because its fibers are much longer than those of wood, new methods for paper production have been needed.
Kenaf is very absorbent and can be used for potting mixes, animal bedding and packing materials. One product made from kenaf, called Bio-Sorb, has been used to soak up oil-contaminated spills. When applied to oil spills on water, the product soaks up oil and then floats so that it can be recovered for incinerating.
Kenaf is grown in more than eight states and more than 18,000 acres will be planted this year. It is hoped that kenaf can serve as a replacement crop for tobacco in southern states. Twenty-eight newspapers have made a commitment to use kenaf newsprint from a mill in Texas that was slated to start in late in 1999. The mill will be capable of supplying about 10 percent of the newspapers’ annual consumption of newsprint and has environmental permits to allow its waste water to be used to irrigate additional kenaf fiber corps.
This article appeared in Wise Traditions in Food, Farming and the Healing Arts, the quarterly magazine of the Weston A. Price Foundation, Summer 2000.