Hemp (from Old English hænep) is the name of the soft, durable fibre that is cultivated from plants of the Cannabis genus, cultivated for commercial use. In modern times, hemp has been used for industrial purposes including paper, textiles, biodegradable plastics, construction, health food, fuel, and medical purposes with modest commercial success. In the past three years, commercial success of hemp food products has grown considerably.
Hemp is one of the faster growing biomasses known, producing up to 25 tonnes of dry matter per hectare per year, and one of the earliest domesticated plants known. For a crop, hemp is very environmentally friendly, as it requires few pesticides and no herbicides. Modern research data on soil fertility is limited. Currently, results indicate that high yield of hemp may require total nutrient levels (field plus fertilizer nutrients) similar to a high yielding wheat crop.
Cannabis sativa L. subsp. sativa var. sativa is the variety grown for industrial use, while C. sativa subsp. indica generally has poor fibre 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, although they can also be distinguished genetically. Oilseed and fibre varieties 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 cultivars of Cannabis grown for marijuana can contain anywhere from 6 to over 20%.
Hemp is produced in many countries around the world. Major producers include Canada, France, and China. While more hemp is exported to the United States than to any other country, the United States Government does not consistently distinguish between marijuana and the non-psychoactive Cannabis used for industrial and commercial purposes.
Hemp is used for a wide variety of purposes, including the manufacture of cordage of varying tensile strength, clothing, and nutritional products. The bast fibres can be used in 100% hemp products, but are commonly blended with other organic fibres such as flax, cotton or silk, for apparel and furnishings, most commonly at a 55%/45% hemp/cotton blend. The inner two fibres of hemp are more woody, and are more often used in non-woven items and other industrial applications, such as mulch, animal bedding and litter. The oil from the fruits (“seeds”) oxidizes (commonly, though inaccurately, called “drying”) to become solid on exposure to air, similar to linseed oil, and is sometimes used in the manufacture of oil-based paints, in creams as a moisturizing agent, for cooking, and in plastics. Hemp seeds have been used in bird seed mix as well. Hempseed is also widely used as a fishing bait.
Hemp seeds contain all the essential amino acids and essential fatty acids necessary to maintain healthy human life. The seeds can be eaten raw, ground into a meal, sprouted, made into hemp milk (akin to soy milk), prepared as tea, and used in baking. The fresh leaves can also be eaten in salads. Products range from cereals to frozen waffles, hemp tofu to nut butters. A few companies produce value added hemp seed items that include the seed oils, whole hemp grain (which is sterilized by law), dehulled hemp seed (the whole seed without the mineral rich outer shell), hemp flour, hemp cake (a by-product of pressing the seed for oil) and hemp protein powder. Hemp is also used in some organic cereals, for non-dairy milk somewhat similar to soy and nut milks, and for non-dairy hemp “ice cream.”
Within the UK, the Department for Environment, Food and Rural Affairs (Defra) has treated hemp as purely a non-food crop. Seed appears on the UK market as a legal food product, and cultivation licences are available for this purpose. In North America, hemp seed food products are sold, typically in health food stores or through mail order. The United States Department of Agriculture estimates that “the market potential for hemp seed as a food ingredient is unknown. However, it probably will remain a small market, like those for sesame and poppy seeds.”