A wonder material that is gentle on the planet has uses in construction, paper, clothing and food – Steve Allin
In a world where ‘economic growth’ may not be desirable, materials will have to come from the environment around us. One wonder material is a controversial crop called hemp. Hemp is a commonly used term for varieties of the cannabis plant and its products, which include oil, fibre and seed. Hemp can provide fibre and biomass from the stem and high quality food from the seeds and has great benefits for the land it is grown upon.
I have been involved with trials and research of Hemp here in Ireland for the last 15 years. Hemp crops have been grown in many areas of the country over this time including counties Cavan, Clare, Down, Kerry, Kildare, Roscommon and Tipperary, So far we don’t have the type of processing equipment needed to turn the crop into a marketable product, but I and others are working on what will become the world’s first hemp combine harvester. Many of the 25,000 uses identified for the plant will be displayed in the Dublin Hemp Museum opening soon in the basement of the Hemp Shop on Capel St, Dublin.
Hemp has been grown for at least the last 12,000 years for fibre (textiles and paper) and food. Because of its importance for sails (the word “canvas” is rooted in “cannabis”) and rope for ships, hemp was a key crop in the American colonies. George Washington and Thomas Jefferson both grew hemp and the Declaration of Independence was drafted on hemp paper. But it has been effectively prohibited in the United States since the Marijuana Tax Act of 1937, which placed an extremely high tax on marijuana and made it effectively impossible to grow industrial hemp. This is despite the fact that the dangers of confounding marijuana and hemp are negligible. Marijuana is grown widely spaced to maximise leaves. Hemp is grown in tightly-spaced rows to maximize stalk and is usually harvested before it goes to seed.
Because of hempís long fibres, the products are stronger and/or lighter than those made from wood
Hemp grows well in a variety of climates and soil types. Hemp is especially conducive to sustainable and organic agriculture. It is naturally resistant to most pests, precluding the need for pesticides. Its tight-spacing squeezes out weeds, so herbicides are not necessary. It also leaves a weed-free field for a following crop.
It produces up to four tonnes per acre per year. After processing its stems, two materials are produced; hurds and fibres. Both hurds and fibres have properties that make them useful in building construction. Rudolph Diesel designed his engine to run on hemp oil. Henry Ford experimented with hemp to build car bodies. He wanted to build and fuel cars from farm products. More recently BMW has been experimenting with hemp materials in automobiles as part of an effort to make cars more recyclable.
Because of hemp’s long fibres, the products are stronger and/or lighter than those made from wood. Construction products such as medium-density fibre-board, and even beams, studs and posts could be made out of hemp. Hempcrete is a bio-composite made of the inner woody core of the hemp plant mixed with a lime-based binder. The hemp core or “shiv” has a high silica content which allows it to bind well with lime. This property is unique to hemp among all natural fibres. The result is a lightweight cement-like insulating material a seventh the weight of concrete. Hempcrete blocks float.
Hemp fibres are longer, stronger, more absorbent and more mildew-resistant than cotton. Fabrics made of at least one-half hemp block the sun’s UV rays more effectively than other fabrics. Hemp can replace cotton which is usually grown with the aid of chemicals. 50% of all the world’s pesticides are sprayed on cotton.
Hemp can be made into fine quality paper. The long fibres in hemp allow such paper to be recycled several times more than wood-based paper. Because of its low lignin content, hemp can be pulped using fewer chemicals than wood. Its natural brightness obviates the need for chlorine bleach, which averts the dumping of toxic dioxins.
Nutritionally, hemp oil is the richest known source of polyunsaturated essential fatty acids (‘good’ fats). It’s high in some essential amino acids, including gamma linoleic acid (GLA), a very rare nutrient also found in mother’s milk. While the original frugal “gruel” was made of hemp-seed meal, hemp oil and seed can easily be made into nutritional products.
Hemp has been touted as a tool to ‘Save the Planet’ but as I illustrate in my stand-up show, “Hemp Can’t Save the Planet but It Might Save Humanity” by clothing, feeding, housing and transporting us.
Steve Allin gave a talk on the wonders of hemp on June 27th at 8.00pm downstairs in the Ormond Wine Bar, 6 Upper Ormond Quay, Dublin 7. A book of the show will be published later this year.