Hemp (from Old English hænep, see cannabis (etymology)) is the common name for plants of the entire genus Cannabis, although the term is often used to refer only to Cannabis strains cultivated for industrial (non-drug) use.
Industrial hemp has been tried for many uses, including paper, textiles, biodegradable plastics, construction, health food, and fuel, with modest commercial success. In the past three years, commercial success of hemp food products has grown considerably.
Hemp is one of the fastest growing biomasses known, producing upto 25 tonnes of dry matter per hectare per year, and one of the earliest domesticated plants known. For a crop, hemp is relatively environmentally friendly as it requires few pesticides and no herbicides.
Cannabis sativa L. subsp. sativa var. sativa is the variety grown for industrial use in Europe, Canada, and elsewhere, while C. sativa subsp. indica generally has poor fiber 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 by genetic means. Strains 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 Cannabis grown for marijuana can contain anywhere from 6 or 7 % to 20% or even more.
Industrial 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