- Hemp has been grown for at least the last 12,000 years for fiber (textiles and paper) and food. It has been effectively prohibited in the United States since the 1950s.
- George Washington and Thomas Jefferson both grew hemp. Ben Franklin owned a mill that made hemp paper. Jefferson drafted the Declaration of Independence on hemp paper.
- When US sources of "Manila hemp" (not true hemp) was cut off by the Japanese in WWII, the US Army and US Department of Agriculture promoted the "Hemp for Victory" campaign to grow hemp in the US.
- Because of its importance for sails (the word "canvass" is rooted in "cannabis") and rope for ships, hemp was a required crop in the American colonies.
- Henry Ford experimented with hemp to build car bodies. He wanted to build and fuel cars from farm products.
- BMW is experimenting with hemp materials in automobiles as part of an effort to make cars more recyclable.
- Much of the bird seed sold in the US has hemp seed (it's sterilized before importation), the hulls of which contain about 25% protein.
- Hemp oil once greased machines. Most paints, resins, shellacs, and varnishes used to be made out of linseed (from flax) and hemp oils.
- Rudolph Diesel designed his engine to run on hemp oil.
- Kimberly Clark (on the Fortune 500) has a mill in France which produces hemp paper preferred for bibles because it lasts a very long time and doesn't yellow.
- Construction products such as medium density fiber board, oriented strand board, and even beams, studs and posts could be made out of hemp. Because of hemp's long fibers, the products will be stronger and/or lighter than those made from wood.
- Over 25,000 products can be made from hemp!
- Industrial hemp and marijuana are both classified by taxonomists as Cannabis sativa, a species with hundreds of varieties. C. sativa is a member of the mulberry family. Industrial hemp is bred to maximize fiber, seed and/or oil, while marijuana varieties seek to maximize THC (delta 9 tetrahydrocannabinol, the primary psychoactive ingredient in marijuana).
- While industrial hemp and marijuana may look somewhat alike to an untrained eye, an easily trained eye can easily distinguish the difference.
- Industrial hemp has a THC content of between 0.05 and 1%. Marijuana has a THC content of 3% to 20%. To receive a standard psychoactive dose would require a person to power-smoke 10-12 hemp cigarettes over an extremely short period of time. The large volume and high temperature of vapor, gas and smoke would be almost impossible for a person to withstand.
- If hemp does pollinate any nearby marijuana, genetically, the result will always be lower-THC marijuana, not higher-THC hemp. If hemp is grown outdoors, marijuana will not be grown close by to avoid producing lower-grade marijuana.
- Hemp fibers are longer, stronger, more absorbent and more mildew-resistant than cotton.
- Fabrics made of at least one-half hemp block the sun's UV rays more effectively than other fabrics.
- >Many of the varieties of hemp that were grown in North America have been lost. Seed banks weren't maintained. New genetic breeding will be necessary using both foreign and domestic "ditch weed," strains of hemp that went feral after cultivation ended. Various state national guard units often spend their weekends trying to eradicate this hemp, in the mistaken belief they are helping stop drug use.
- A 1938 Popular Mechanics described hemp as a "New Billion Dollar Crop." That's back when a billion was real money.
- Hemp can be made into a variety of fabrics, including linen quality.
- The US Drug Enforcement Agency classifies all C. sativa varieties as "marijuana." While it is theoretically possible to get permission from the government to grow hemp, DEA would require that the field be secured by fence, razor wire, dogs, guards, and lights, making it cost-prohibitive.
- The US State Department must certify each year that a foreign nation is cooperating in the war on drugs. The European Union subsidizes its farmers to grow industrial hemp. Those nations are not on this list, because the
- State Department can tell the difference between hemp and marijuana.
- Hemp was grown commercially (with increasing governmental interference) in the United States until the 1950s. It was doomed by the Marijuana Tax Act of 1937, which placed an extremely high tax on marijuana and made it effectively impossible to grow industrial hemp. While Congress expressly expected the continued production of industrial hemp, the Federal Bureau of Narcotics lumped industrial hemp with marijuana, as it's successor the US Drug Enforcement Administration, does to this day.
- Over 30 industrialized democracies do distinguish hemp from marijuana. International treaties regarding marijuana make an exception for industrial hemp.
- Canada now again allows the growing of hemp.
- Hemp growers can not hide marijuana plants in their fields. Marijuana is grown widely spaced to maximize leaves. Hemp is grown in tightly-spaced rows to maximize stalk and is usually harvested before it goes to seed.
- Hemp can be made into fine quality paper. The long fibers in hemp allow such paper to be recycled several times more than wood-based paper.
- Because of its low lignin content, hemp can be pulped using less chemicals than with wood. Its natural brightness can obviate the need to use chlorine bleach, which means no extremely toxic dioxin being dumped into streams. A kinder and gentler chemistry using hydrogen peroxide rather than chlorine dioxide is possible with hemp fibers.
- Hemp grows well in a variety of climates and soil types. It is naturally resistant to most pests, precluding the need for pesticides. It grows tightly spaced, out-competing any weeds, so herbicides are not necessary. It also leaves a weed-free field for a following crop.
- Hemp can displace cotton which is usually grown with massive amounts of chemicals harmful to people and the environment. 50% of all the world's pesticides are sprayed on cotton.
- Hemp can displace wood fiber and save forests for watershed, wildlife habitat, recreation and oxygen production, carbon sequestration (reduces global warming), and other values.
- Hemp can yield 3-8 dry tons of fiber per acre. This is four times what an average forest can yield.
- If one tried to ingest enough industrial hemp to get 'a buzz', it would be the equivalent of taking 2-3 doses of a high-fiber laxative.
- At a volume level of 81%, hemp oil is the richest known source of polyunsaturated essential fatty acids (the "good" fats). It's quite high in some essential amino acids, including gamma linoleic acid (GLA), a very rare nutrient also found in mother's milk.
- While the original "gruel" was made of hemp seed meal, hemp oil and seed can be made into tasty and nutritional products.
Prepared by the North American Industrial Hemp Council, October 1997
Hemp Plant Uses
The hemp plant is harvested for its fibers, seed, seed meal and seed oil. Hemp is a distinct variety of the plant species cannabis sativa L. Due to the similar leaf shape, hemp is frequently confused with marijuana. Although both plants are from the species cannabis, hemp contains virtually no THC (delta-9-tetrahydrocannabinol), the active ingredient in marijuana. Hemp cannot be used as a drug because it produces virtually no THC (less than 1%), where marijuana produces between 5 - 20 % THC.
Hemp Agronomic Characteristics
Hemp is a bast fiber plant similar to flax, kenaf, jute and ramie. Long slender primary fibers on the outer portion of the stalk characterize bast fiber plants. An annual plant that grows from seed, hemp can be grown on a range of soils, but tends to grow best on land that produces high yields of corn. The soil must be well drained, rich in nitrogen, and non-acidic. Hemp requires limited pesticides because is grows so quickly and attracts few pests. In northern latitudes, hemp is usually planted between early March and late May. Hemp averages between 2 - 4 meters in height in about four months of growth.
Hemp crops are harvested at different times for different hemp products.
- Harvesting stalks for high-quality primary fiber occurs as soon as the crop is in flower.
- Harvesting for seed production and stalks occurs 4 - 6 weeks after flowering, when male plants begin to shed pollen.
Primary Hemp Fiber
The valued primary fibers are contained around the hollow, woody core of the hemp stalk. These long, strong fibers that grow the length of the hemp stalk are considered bast fibers Hemp fiber possesses properties similar to other bast fibers (flax, kenaf, jute and ramie) and excels in fiber length, strength, durability, absorbency, antimildew and antimicrobial properties.
Once a hemp crop has matured and been harvested, hemp primary fibers are separated from the hemp stalk through the "retting" process. For "dew retting", the cut stalks are left in the field for several weeks to allow natural humidity and bacteria to decompose the fiber-binding pectins. Other ways to separate the fiber from the core are: water retting, warm water retting and chemical retting. When the retting process is complete, the fibers are readily separated from the core, and processed for specific products.
Primary fibers are long-staple length fibers, averaging 8 ” (20 cm) in length. These hemp fibers can be spun and woven to a fine, crisp, linen-like fabric and used for apparel textiles, home furnishing textiles and carpeting. Antimildew and antimicrobial properties make them very suitable for sails, tarps, awnings, and floor coverings.
Primary fibers can be cut to shorter staple lengths to accommodate a variety of spinning systems. Hemp fiber blended with wool, cotton, linen or other fibers, adds strength, durability, absorbency and breathability, making hemp blended fabrics cool and comfortable to wear and touch.
Qualities of Primary Hemp Fiber
- length average 8 ” (20 cm) in length,
- 4 - 6 ”, 1 - 2 ” and special lengths available upon request
- luster high
- strength high
- elasticity low, can be treated to improve
- heat conductivity high, very cool fabric to wear
- absorbency high
- cleanliness and washability high
- reaction to bleaches will weaken, use with care
- reaction to heat will scorch and burn
- effect of mildew highly resistant
- effect of light & outdoor exposure very resistant
- reaction to alkalies not affected
- reaction to acids easily affected
- affinity for dyes very good
Core fiber is derived from the sturdy, wood-like hollow stalk of the hemp plant. Sometimes referred to as "hurds", it is up to twice as absorbent as wood shavings, making it an excellent animal bedding and garden mulch. It can be easily blended with lime to create a strong yet lightweight concrete or plaster. It's high cellulose content means it can be applied to the manufacturing of plastics. Like primary fiber, it is biodegradable and possesses antimildew and antimicrobial properties.
U.S. Legal Definitions
Custom Regulations of the United States, Official US Custom House Guide, 1987. sec. 302.58 --CR-360. MARIJUANA STATUTORY PROVISIONS
Controlled Substances Act, Food & Drug Admin (1970)
Chapt. 22, Sec. 802-15 Definitions:
(a) MARIHUANA. The term 'marihuana' means all parts of the plant Cannabis sativa (L.), whether growing or not, the seeds thereof, the resin extracted from any part of such plant; and every compound, manufacture, salt, derivative, mixture or preparation of such plant, its seeds or resin;
BUT SHALL NOT INCLUDE the mature stalks of such plant, fiber provided from such stalks, oil or cake made from the seeds of such plant., any other compound, manufacture, salt, derivative, mixture or preparation of such mature stalks (except the resin extracted therefrom), fiber. oil or cake or the sterilized seed of such plant. which is incapable of germination.....
Hemp Seed Uses
Whole Hemp Seeds
Available in sterilized, toasted,roasted and fractionalized (cracked) forms, they are rich in protein, vitamins and minerals. They can be cold-pressed for oil, or hulled to expose the seed meat. Hemp seeds are the only edible seeds with gamma-linolenic acid (GLA).
Hulled Hemp Seed
Hemp seed is a highly nutritious source of protein, better tasting and more digestible than the soybean.
Whole hemp seeds can be toasted for snack food or ground into flour. Hulled hemp seed are a healthful component of baked goods, snack and protein bars, granola, sauces and dips. Very versatile, hulled hemp seeds can even be processed into milk, cheese, ice cream, margarine and other foods. Most bird seed contains hemp seed and it makes an excellent ingredient in many pet and animal foods.
Hemp Seed Oil
Hemp also produces an oil seed that contains between 25 - 35 % oil by weight, which is high in essential fatty acids. Cold-pressed, unrefined hemp oil is light green, with a nutty grassy flavor. It is a superb nutritional supplement for EFA and imparts a desired flavor into dressings, dips and spreads. It can be combined with or used in replacement of olive, walnut and safflower oils for eating. Note that you should not cook with hemp seed oil because heating to temperatures high enough for cooking can diminish or destroy hemp oil’s nutritional values.
Refined hemp oil is clear with little flavor or nutrients and has been widely used in body care products, lubricants, paints and industrial uses. Antimicrobial properties make it an ideal base for soaps, shampoos and detergents.
Hemp Seed Meal
Even after the hemp seed has been crushed for oil, the remaining product still contains 25% protein and is an excellent source of dietary fiber - it still remains a very appropriate food ingredient and nutritional supplement for people and animals. It can be used to brew beer.
Hemp Horizons by John Roulac, Chelsea Green Publishing Company, 1997
Agriculture and Agri-Food Canada