Hemp is promoted online as a miracle plant that could save us from environmental destruction and nutritional problems. Should we believe those claims?
Hemp production was banned in the United States under the Marijuana Taxation Act of 1937. This also included industrial hemp, a subspecies of Cannabis sativa. This variety contains smaller amounts of tetrahydrocannabinol (THC), the psychoactive principle of Cannabis. Instead, several positive properties are attributed to this hemp on the internet. It should have the potential to protect us from environmental problems.
Under a new 2018 farm law, the U.S. government allowed again the production of this hemp species. So farmers can now grow the plant on a large scale. But can this really revolutionize everything from the textile industry to the construction industry?
The researchers suspect that part of the hype comes from hemp lobbyists, who, in the fight to legalize the plant, did not take science too seriously. But studies also suggest that hemp, with the help of targeted investments, could replace some less sustainable materials.
So which statements are correct and which are not?
Statement 1: Hemp is the oldest known crop, dating back over 12,000 years.
Most of the findings show that humans started growing plants about 10,000 years ago, in Mesopotamia. However, there is little evidence that hemp was among them. Still, the relationship between hemp and humanity is long. Archaeological findings show that it was already cultivated over 4,000 years ago in China to produce paper, cloth, rope, and oil from its seeds.
Statement 2: we can use Hemp in 25,000 products.
Hemp is a versatile plant, as its various parts, from stem to flower, can theoretically be used “for our home, and for dressing,” according to Lawrence B. Smart, a professor at the School of Integrative Plant Sciences from Cornell University in New York State, which investigates the potential of hemp cultivation on an industrial scale.
The plant is also a valuable source of gluten-free and soy-free protein, and rich in omega-3 and 6 fatty acids, found mainly in fish. Therefore, it is suitable as a dietary supplement for vegans and animal food, according to Smart. “I think the statement of its multiple-use, for example, as fibre or as a medical product, is correct,” he says to DW. The question is whether it is “cheaper, better or more sustainable than the products we use on the market,”.
Statement 3: Hemp biofuels could fuel a green revolution in transportation.
Hemp as a biomass crop (its stems are rich in cellulose) or hemp oil as a biofuel could be a complement to other renewable energy sources. But like other energy crops, there are problems inherent in large-scale growth. Despite claims it does not need fertilizers, hemp, like corn, requires a lot of nitrogen.
“I don’t assume we’ve got done the correct life cycle assessments to assert that hemp offers any advantage over exploitation biofuels from corn,” says good. “It produces an affordable yield per area unit, however different crops are way more property.”, it states. Smart’s research group at Cornell University is investigating several potential energy crops. His research so far suggests that willow, a perennial, may be more sustainable than an annual plant like hemp. This is because the willow is planted once and can then be regularly harvested without having to work the soil for 25 to 30 years. And it is that every time a field is cultivated or ploughed, carbon is released into the atmosphere.
Statement 4: Hemp grows in poor soils and does not require pesticides.
Another widespread claim is that hemp grows on its own. But because it was not cultivated on a large scale during the 20th century, there are hardly any studies that show whether it grows easily in poor soils.
The first minor investigations in Italy and the USA they show promising results, for example regarding hemp’s ability to remove toxins from the soil. The researchers have also found that if the plant is grown under the right conditions; it does not have to be treated with herbicides due to its rapid growth. Hemp contains cannabinoids and terpenes, compounds that can scare away insects. But Smart cautions against claims that pesticides would not be needed.
“We have found a variety of insect pests that injury hemp, furthermore as some diseases, together with new plant life species that are being studied,” says sensibly. The Pennsylvania State University agricultural analysis laboratory also found that the pests like aphids, mold, and slugs can harm the hemp plant.
“If you plant a little garden plot of six by six meters, it’s unlikely to expertise the total vary of pests and pathogens that will be expected on eight thousand hectares,” says good. Industrial agriculture of any monoculture leads to environmental problems, for which depends on how the plant is grown.
Statement 5: Hemp could replace petroleum-based plastics and we could live in houses made of hemp.
Companies like Zeoform in Australia and Kanesis in Italy are producing small amounts of bioplasmic from hemp. But at the moment, the production of hemp plastics is too complicated, requires a lot of energy and is expensive, so it will not offer an alternative to oil-based varieties soon.
Still, hemp is proving to be a popular alternative to fibreglass for compressed panels. The automaker BMW, for example, is using hemp on its door panels. It is also sustainable building material.
The misleading name “hemp concrete” is not a substitute for concrete, but is an insulating material suitable for half-timbered houses. It is very popular in France, although it is more expensive than conventional alternatives. According to Pete Walker, professor at Department of Civil Engineering and Architecture of the University of Bath (England), has advantages.
“It is a renewable resource,” says Walker. “It is possible to grow hemp in four months, removing carbon dioxide from the atmosphere and attaching it to plant material.” Its breathable structure also regulates the temperature and humidity of a building, reducing energy consumption.
Statement 6: Hemp consumes 25 to 50 percent less water than cotton.
Recent comparative studies between cotton and hemp are difficult to get. One of the most extensive reports, published by the Stockholm Environment Institute in 2005. It compared the two natural fibers with polyester, a synthetic material.
The study concluded that cotton consumes about 50 percent more water than hemp in one growing season. Unlike hemp, cotton requires a lot of irrigation and is often grown in water-poor regions like Uzbekistan.
However, it is not as simple as swapping one fiber crop for another. Hemp, while durable, is also expensive and requires a lot of energy to produce a smooth fabric. Long hemp fibers are processed differently than short cotton fibers. The industry would have to renew its machinery to make the change.
Statement 7: The US Constitution was written on hemp.
The National Constitution Center and the data verification website Politifact completely refute one of the most outrageous claims about hemp circulating on the internet. The United States Constitution, the Declaration of Independence and the Bill of Rights are written on parchment, which is treated animal skin.
The Constitution Center admits, however, that drafts of these documents could well have been made on hemp paper. As the plant was widely cultivated in North America for manufacturing rope and candle. Hemp was grown by George Washington and Thomas Jefferson. They were the country’s first and third president respectively, and two of the founding fathers of the United States.