Industrial Hemp: An Ancient Multipurpose Crop

by Michele Warmund, University of Missouri, Division of Plant Sciences, modified and submitted by Cathy Bylinowski, Horticulture Instructor, MU Extension- Jackson County, MO
 

     Although industrial hemp (Cannabis sativa) is considered a new crop in Missouri, it is actually an ancient crop, which was harvested in China 8500 years ago.  
     Fiber hemp was introduced to western Asia and Egypt, and then into Europe between 1000 and 2000 BCE. Hemp was imported into North America in 1606. Missouri was a major producer of fiber hemp from 1840 to 1860 due to the demand for sailcloth and rope. 
     Hemp was primarily grown in Kentucky until World War I. However, the Marijuana Tax Act ended fiber hemp production in 1938, except for a brief production period from 1942 to 1945 when 400,000 acres produced fiber for cloth and cordage.
     Industrial hemp could again be an important alternative crop for Missouri farmers. It is the job of University of Missouri as a state research university to determine the best way to do that. Research will focus on both ideal growing conditions and potential economic impact.
 
Industrial Hemp is not Marijuana.    
     Although the plant used to grow industrial hemp is the same plant as used to grow marijuana, they are different varieties, which means they have extensive botanical differences – the main difference being that industrial hemp has less than 0.3 percent THC. It cannot be used as a recreational drug.
     Hemp is one of the oldest sources of textile fiber. The bast fibers in the phloem of the stem tissue ("bark") range from 0.2 to 1.6 inches long, while the stem core fibers, known as hurds, are shorter. 
     Textiles made with bast fiber are strong and durable, with high tensile and wet strength. Thus, bast fibers were used extensively for rope, nets, canvas, sailcloth, and oakum for caulking on ships. Fiber hemp was also valued for upholstery, bags, sacks, and tarpaulins during this time. Today, hemp is used in materials for clothing and footwear.
     During the 1800's, paper was made primarily from hemp and flax. Later, the development of cheap wood pulping methods for paper production was more economical than processing hemp and flax fibers. Today, specialty hemp paper products made from bast fibers include art papers, tea bags, bank notes, and technical filters.
     Presently, hemp fiber is incorporated into plastic composites for molded car parts in Europe. Henry Ford used hemp and soybean to make durable car parts, such as trunk doors, in the 1940's. In car parts with fiber hemp, there is no splintering in accidents.
     It provides favorable mechanical and acoustical properties. Hemp composites may have other uses in the manufacturing of bicycles, airplanes, and other vehicles for lightweight parts, padding, or sound insulation.
     Fiber hemp is used in building construction products for thermal insulation, fiberboard, and in cement and plaster to enhance the strength of building materials.
     For fiberboard, the short hurd fibers are used in composite wood products. The addition of hemp fibers into concrete also reduces shrinkage and cracking.
     Hemp hurds can also be chemically combined with other products to strengthen foundations, walls, floors and ceilings of structures, or to make tile-like products.
     Outdoor products made from hemp fibers, such as hemp fiber netting or blankets, can prevent soil erosion and stabilize new plantings. Horticultural uses for hemp fiber include biodegradable pots and biodegradable twine or supports for plants and trees in landscapes, orchards, and vineyards, replacing plastic ties.   
     Hemp hurds are also useful for animal bedding and pet litter.
Hulled hemp seed and cold-pressed hempseed oil can be used for specialty food products, beverages, nutraceuticals, and cosmetics in North America. Due to the nutty flavor of hemp seeds, they are included in some food products.
     As with any "new" crop, there are pitfalls for producers, including growing challenges, potential for overproduction, new laws, and a lack of secure markets.
     For consumers, fiber hemp offers alternative products. Currently, market expansion of non-food hemp products is limited by crop availability and high costs associated with fiber extraction and manufacturing processes. However, with innovative solutions, technical challenges can be overcome.