Hemp is the common name for the plant Cannabis sativa L. This plant is a tall annual herbaceous plant with a deep tap root system. Its height is between 1 and 5 meters, depending upon the climate and the soil conditions in which it is cultivated. It has a single slender main stem- 4 to 20 mm thick. Normally it is dioecious, that is has seperate male and female plants. However, monoecious (both sexes in the one plant) have been bred. The male plant produces pollen and is termed staminate, while the female plants are termed pistillate and produce seeds. The male plants soon die after the pollen is shed, while the female plants continue to live until the seeds have matured. This plant can be produced into a great variety of products ranging from paper to fabrics, food and fuel.
The stem of the hemp plant is hollow except at the base and tip. The fibres of the stem can be broken down into 2 distinct groups- the bark or the bast (the outer stem tissues), and the core or hurd (the inner stem tissues). The bast is the most valuable component for paper or textile production. This bark section contains 2 fibre types- promary and secondary bast fibres. These are thick walled with a high cellulose and low hemicellulose and lignin content. This means less chemicals are needed in production processing compared to wood pulp techniques. The woody core or hurd fibres are thin walled and are short. They have a lower lignin content which means there is a better chance of using non-chlorine bleaching or the production of unbleached pulp.
Stem fibres are used to produce:
- paper- as fine as cigarette papers or as strong as corrugated cardboard, to add strength to improve the quality in wood or straw based paper.
- textiles- ranging from high quality fashion fabrics to durable and everyday cloth, sewing thread to rope.
building materials- ranging from insulation, paneling, medium-density fibreboard, trusses and support beams. Laboratory results (Washington State University's Wood Composite Laboratory) have shown hemp used in place of wood for medium-density fibreboard has twice the strength.
The seeds of the Cannabis sativa L. plant are small and brown to grey in colour. They have an oil content of 35% and a protein content of 25%. The seeds are highly nutrious and can be used in the same manner as soya beans. Hemp oil (produced from the seeds) has a high vitamin content and this, along with the essential fatty-acid content of the seeds, help to assist the body's natural healing ability. Also they can be used in paint varnishes, as well as in cosmetics, shampoos and bath gels.
The roots are a deep tap root system which is very beneficial to the soil as it allows aeration. As the roots are deep, the plant is able to take advantage of deep subsoil moisture.
The leaves are not used in the production of paper or textiles, but are useful for the soil. After harvest leaves are left on the ground which results in maximum nutrient recycling. As the plants grow the leaves create quite a dense canopy, resulting in limited light reaching the ground level helping to choke out weeds. The leaves, along with the flowers in non low-THC varieties of cannabis, can be used for medicinal purposes ranging from treatment of glaucoma, muscle spasms and vomiting.
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