Hemp seems to have got itself a bad name by association with its relative marijuana. Their parent plant is the Cannabis Sativa, but the similarities pretty much end there.
The History of Hemp
Humans have been cultivating hemp for millennia – in fact, it is one of the earliest known agricultural plants that we grew, dating back to the end of the Stone Age in China. The ancient Chinese used the bast fibres from the outer stem to make ropes; they ground down the inner, woody fibres (the hurds) to make pulp for a primitive form of paper. They also developed a technique for weaving fibres together to make textiles for clothes – the West only caught up when they were well into the Iron Age.
Hemp is known for being very adaptable to different soils and different climates, making it one of the sturdiest plants. Archaeological evidence of hemp growing has been found all over the globe.
When international trade kicked off in the mid-1800s, sailing ships were rigged with hemp sails and ropes, which were strong and tough. They had to be tarred to prevent rotting, which earned sailors the nickname ‘Jack Tar’. However, the introduction of manila, a fibre sourced from the abacá tree that didn’t require tarring, reduced the popularity of hemp.
Global production of hemp still remained high into the mid-1940s: 350,000 tonnes of hemp per year was produced to make everything from uniforms to canvases for World War II. The word ‘canvas’ likely derived from ‘cannabis’, the plant family name. However, after WWII the production of hemp dropped to 75,000 tonnes per year due to crackdowns on the growth of recreational drugs like its cousin marijuana.
The Main Difference Between Hemp And Marijuana
In fact, the fears over the growth of hemp are completely unfounded. Marijuana contains much higher levels of THC (delta 9 tetrahydrocannabinol), the chemical that causes psychoactive effects, than hemp. According to the North American Industrial Hemp Council, “Industrial hemp is bred to maximize fiber, seed and/or oil, while marijuana varieties seek to maximize THC […] Industrial hemp has a THC content of between 0.05 and 1%. Marijuana has a THC content of 3% to 20%.”
If you tried smoking hemp, you’d have to smoke 10-12 hemp cigarettes to get the standard psychoactive dose. The vapour, gas and smoke would give you a headache and it would be impossible to continue.
For more reasons why hemp can’t be used as a substitute for marijuana, read The Weed Blog’s article on the misconceptions of hemp.
The Benefits of Hemp Farming
Industrial hemp is always densely planted to encourage the growth of tall stalks for longer fibres. Hemp grows as tall as 6m high (20 ft) in 108-120 days, and this means that even tough weeds are eliminated easily in hemp fields, decreasing the volume of herbicides needed.
Only about 8 of about 100 known pests cause problems, meaning that hemp can easily be grown organically without herbicides, pesticides or fungicides.
Hemp guzzles a lot of water and nutrients, so it can be used as a ‘mop crop’ to clean up wastewater. Experiments have used hemp to clean contaminants from the ground around the nuclear disaster area in Chernobyl, Russia.
What Can Hemp Do For Us?
We can take inspiration from the ancient Chinese. Almost all of the parts of the plant can be used for a huge variety of applications; here I list a few. (If you can’t be bothered to read through it, scroll through these images, which will give you an idea of the diversity of applications).
- Hemp can be used for making clothes that block UV light more effectively than other fabrics. Hemp fibres are stronger, more absorbent and more mildew-resistant than cotton. They can be blended with other organic fibres like flax, silk and cotton to create different textures. Hemp fibres have also been found to be antibacterial, and could replace cotton or polyester fabrics in hospitals to prevent infection.
- Hemp can smooth the transition from petrol to biofuels. Hemp seed oil can be combined with the stalks and ethanol from the fermentation of the whole plant to create biodiesel, also referred to as ‘hempoline’. Hemp can also provide energy in other forms, from fuel pellets to liquid fuels and gas. In fact, Henry Ford’s first car was designed using hemp in the body and as a fuel, so this technology is well within reach. The use of hemp as biomass fuel requires the least specialised cultivation and processing procedures of all the hemp products.
- As mentioned above, hemp can be used as a lightweight building material, which is essential to the automotive industry. The majority of car manufacturers, from Iveco to Porsche, have incorporated hemp into composites similar to fibreglass. BMW shed 10% of the weight of the door panels of its i3 model by using a hemp-plastic composite. Over 2 million cars on the road today have hemp composites used in door panels, dashboards, luggage racks etc. Not only for use in cars, hemp can be combined with lime to create ‘hempcrete’, an insulating and moisture-regulating material. Hemp-based fibreboards are found to be twice as strong as wood-based fibreboard, with no more resin required.
- Hemp seed is a high-protein health food, containing more essential fatty acids than any other source and its complete protein content second only to soya beans (but hemp proteins are more digestible). Hemp contains a lot of dietary minerals such as magnesium, zinc, iron and B-vitamins and is also a good source of fibre. In the USA, the value of hemp-based cosmetics and food supplements totalled $184m in 2013, according to the Hemp Industries Association.
- Hemp fibre paper doesn’t decompose or turn yellow as fast as paper from wood pulp when an acid-free process for pulping is used due to its low lignin content. Hemp paper can be recycled more times than wood-based paper. If grown sustainably, hemp produces more pulp per acre than timber. Hemp fibres can make all qualities of paper, and its creamy colour means that less bleaching is required so fewer chemical by-products are produced.
- Biodegradable non-toxic plastic products can also use hemp. Recycled plastic can be mixed with hemp for injection moulding, plant-based cellophane can be created, hemp waste can even be used to create a material for 3D printing which is 20% lighter and 30% stronger than PLA, the standard plastic used.
- Hemp has even branched out to nanotechnology, where capacitors with a graphene-like carbon nanosheet produced from hemp bast fibres can perform similarly or even better than graphene, at a fraction of the cost. This can cause the production of cellulose nanoparticles to be cheaper, leading to uses in batteries, drug delivery and biodegradable plastics.
If this article hasn’t convinced you that hemp is a versatile plant, you should check out IOM3’s article on hemp as their ‘material of the month’ where I derived most of my facts and inspiration. Interestingly, this article on Modern Farmer argues that hemp’s utility is only marginal and the demand is not high enough to support a large hemp industry. If you want more facts on hemp, check out the Eden project’s fact file. If you still have qualms about whether hemp can become a source of THC for recreational drug users, this article on The Weed Blog will blow your doubts out of the water. If you want more information on the relationship between the US and hemp, check out this article by the BBC.
Questions To Think About
So what do you think of hemp? Does it deserve to be a successful plant and break away from the shadow of its cousin marijuana to become a legalised commercial product? Or are the current materials and technologies sufficient?
Also, let me know if you liked this sort of scientific post and want to read more!