Why use hemp?

by Tim Berenyi

Plantchester products are made from hemp because it’s a product from the past here to save our future. 

Human use of hemp goes back at least 6,000 years, making it one of the oldest non-food source crops ever grown (van der Warf et al., 1996)

And before we get any further, hemp is not the same as ganja aka mary jane aka devils lettuce aka marijuana. Hemp by definition contains very low-levels of THC, the psychoactive chemical which gives the 'high'.

To cultivate hemp in Victoria, Tasmania and Western Australia the plants must have less than 0.35% THC, and New South Wales, South Australia and Queensland less than 1%.

In comparison, marijuana contains on average 14-20% THC.

Cultivation was banned in Australia in 1937 and it wasn’t allowed again until 2017 under tight restrictions. Cannibis sativa L. (hemp) originates from central Asia but can be grown from the Equator up to the Polar Circles (van der Warf et al., 1996).

Hemp was unfortunately caught up in the War on Drugs going back as far as the 1950s when it was confused with its psychoactive cousin

So why do we use hemp?

Here are 5 reasons, but there are many more.

1. Hemp requires less water than cotton to grow.

Hemp is a brilliant fibre to use because it requires a fraction of the amount of water to grow compared to other fibre crops such as cotton and flax. Cotton uses between 7000 to 29,000 litres of water to produce 1 kilogram of raw fibre (Kalliala & Nousiainen, 1999). In comparison, hemp requires just over 300 litres to produce a kilogram of usable fibre  (Cherrett et al., 2005).

2. Hemp sequesters more carbon dioxide than any other crop.

The emissions generated during the cultivation of cotton amount to 4.7 kg of CO2e per kilogram of cotton fibre, whilst the crop absorbs 1.65 kg of CO2 as it grows, resulting in the overall production of 3 kg of CO2 to produce a kilogram of cotton (Kalliala & Nousiainen, 1999)

Comparatively, one kilogram of hemp generates 0.1-0.2 kg of CO2 per kilogram of hemp fibre, whilst absorbing 29.33kg of CO2 (Aytaç, 2018). This makes hemp 400% more efficient at absorbing CO2 than any other commercial crop (Aytaç, 2018).

3. Hemp doesn’t need any chemicals.

As a crop, hemp can be produced continually without the cumulative environmental impacts of crops such as cotton. This is because it requires little to no agrochemicals for cultivation due to being naturally pest resistant and drought tolerant (van der Warf and Turunen, 2008). In comparison, crops can be treated with pesticides up to 20 times per season which have subsidiary consequences for the surrounding environment  (van der Warf et al., 1996).

Intensive irrigation and high fertiliser use further compound the environmental impact of cotton production (Pimental et al., 1990). Whereas hemp improves soil structure, virtually resistant to diseases and pests, whilst yielding several times more cellulose than other crops (van der Warf et al., 1996).

4. Hemp can be used for more than just fabric.

Unlike most other fibre crops, hemp can be used for multiple purposes. 

Hemp seeds are high in Omega-3 and Omega-6, vitamin E and minerals - phosphorus, potassium, sodium, magnesium, sulphur, calcium, iron and zinc (Mihoc et al., 2012).

Hemp seeds, by weight, provide similar amounts of protein as beef and lamb; 2–3 tablespoons (30 grams) of hemp seeds provide about 11 grams of protein (Callaway, 2004)

It can also be used in construction as composites for building, hemp cellulose is mixed with hydrated lime which absorbs atmospheric CO2 as it sets (due to the carbonisation of the lime) making it a carbon-positive construction material, absorbing 1.6 to 79 kg CO2e per square metre (Arehard et al., 2020).

5. Hemp is naturally a really great fibre.

Due to the chemical composition of hemp, it is naturally antimicrobial and anti-fungal, which means that it will not rot as quickly as cotton - making it a very durable product.

This is why it was used for ship sails throughout history, dating back to the first Arabic flotillas hemp was used as the rope for rigging, the oils used to condition the timber decks, and the fibre used to pack beds in sleeping quarters (Yano and Fu, 2023)

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