Hemp (Cannabis sativa), a term used to identify both the plant and the fiber it produces, is used to make the strongest and most durable commercial fibers available. Hemp was most likely the first plant cultivated for its fiber. It was cultivated for the purpose of making cloth in China as early as the twentyeighth century b.c.e. It was also used as a drug by the ancient Persians as early as 1400 b.c.e. and was used as the cordage or rope on almost all ancient sailing vessels. Today hemp is commercially produced for heavy textiles in numerous countries, but less than 1,000 acres is devoted to commercial hemp production in the United States. Hemp production is problematic in the United States because it is illegal to grow Cannabis sativa, the source of marijuana.
Hemp is an annual plant in the mulberry family. The plant is dioecious, meaning that it has staminate or "male" flowers and pistil late or "female" flowers. It has a rigid stalk, which can reach a thickness of more than 2.5 centimeters in diameter, and a height of 5 meters. The plant has a hollow stem, and the bark or "bast" located outside the woody shell is used to make the bast fiber, which is then used to make hemp twine, ropes, and other textiles where strength and durability are desired.
Humid climates with moderate temperatures and a period of at least 120 frost-free days are necessary for hemp production. Unlike flax, hemp requires that the soil be plowed and thoroughly disked or harrowed prior to planting. The entire aboveground portion of the plant is harvested when the male plants are in full flower. After two to three days the plants are tied in bundles and set in shocks. Hemp fiber is retted and prepared for the mills in a manner very similar to that of flax except that heavier machines are used to handle the stronger hemp stalks.
See also: Cotton, Flax, Minor Crops
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