Hemp – you may well quite rightly have preconceived notions of the plant that is a close relative to Cannabis, and to an amateurs eye, looks like an identical twin to its controversial cult cousin. 

Hemp is one of the earliest known garment fibres used (dating back to 10,000 BC China) and under Henry VIII in 15th Century England was compulsory to grow due to its hugely useful properties, Hemp was once ubiquitous (Black, 2008). Unfortunately Hemp has had a tough last 75 years after it was marginalised through growing restrictions due to its family ties with Cannabis, though it has almost no psychoactive qualities itself. It was only in December of 2018 that the US Government lifted the restrictions on the growth of industrial Hemp. 

Hemp offers a far more environmentally friendly alternative to cotton in many cases. Using 5 times less water to grow and is 4 times more durable, it needs no fertilisers or pesticides, and is one of the only known plants to actually enrich the soil it grows in rather than deplete it. On a handling level Hemp is often thought of as a coarse material as it was centuries ago however modern technologies can now produce silk like materials. As the world applies pressure to brands to innovate and adapt in such an environmentally conscious time.

Hemp is a quick growing plant that can create biomass which sequesters carbon dioxide in the process, potentially being stored indefinitely. Carbon capture helps form part of circular systems, which has given this material growing attention. Systems are being created that eliminate waste and promote reuse and recycling of resources. As hemp is a natural fibre it is able to biodegrade safely, and shows promise in replacing synthetic fibres. These fibres can be used to create products such as paper and building materials, to bioplastics and livestock bedding. At different stages of the plants cycle the plant produces seeds that can be used to create products such as hemp oil for cooking and seed cake for animal feed.

Housing

Hemp is growingly being used in construction, particularly when creating more eco-friendly buildings. Hempcrete is one solution that has the ability to both offset a carbon-intensive building material and simultaneously provide a long term carbon store. This new composite material is made from wet-mixing hemp shiv with a lime binder. This results in a material that is natural, vapour-permeable and has airtight insulation. 

Designed by Practice Architecture, Flat House at Margent Farm is the conversion of a steel-framed agricultural shed which has been made of prefabricated timber-framed cassettes filled with Hempcrete. Once the mulch of  hemp, lime and water was dry they were erected into thick walls that also hold the building up. The exterior was then covered in corrugated panels made of fibres from the outer coating of hemp stalks combined with resin taken from agricultural waste.

Fuel

Biofuels are much more sustainable than finite fuels. This is due to their ability to grow at a sustainable rate. Biofuels can also be made from hemp. This fuel can be made by using both the fruit and grain of a plant or the fibres of the plants, with hemp being primarily used to produce cellulosic ethanol. The process begins by harvesting the plant before shredding and heating it with chemicals, so that the cellulose is released. Enzymes are then used to break down the cellulose into sugars.Microbes are then introduced to ferment sugars – turning them into ethanol. Finally, the ethanol is purified and distilled.

Hemp is an ideal candidate for biofuel production. Typically biofuels are made from corn or sugarcane due to their high levels of sugar content. But these materials are food sources, meaning that biofuel production can compete with food production. However, hemp leaves and cellulose fibres are not valuable food sources so can be used. Hemp can also be grown quickly and easily in most climates, thus creating more localised production and boosting local economies.

Fibre

Using hemp as fibres for clothing is not a new concept. It is thought that the plant was probably the earliest plant cultivated for textile fibres. Archaeologists found a remnant of hemp cloth in ancient Mesopotamia (currently Iran and Iraq) which dates back to 8,000 BC. Up until the last century it was one of the world’s most significant crops. But due to its growing restrictions and negative connotations the use of hemp in clothing deteriorated. 

The growth and use of industrial hemp has the potential to lower the environmental impacts of textile production, empower small-scale farmers and create jobs in a wide variety of industries. Clothing brand Patagonia has legally-sourced hemp fibre in their clothing lines since 1997. They blend this imported hemp with other fibres such as recycled polyester, organic cotton or spandex. But now, Post Farm Bill, they hope to use local American domestic supplies of hemp. Previously their hemp was sourced in China, where the government heavily subsidised hemp production and has for generations.

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References/Credits:

Robert Nelson

Bonafideseeds

David Grandorge

Margent Farm

Oscar Proctor

Lloyd Belcher

Patagonia