Hemp farming in France nearly died out in the 1970s but the rustic plant, a member of the cannabis family, is making a dramatic return as a low-carbon alternative in the textile and construction industry. France is now Europe's largest producer and has high hopes of doubling production in the next five years.
Cannabis sativa Linn, commonly known as hemp, is a hardy plant going back to medieval times.
Production in France boomed during the 17th and 18th century when its tough fibres were used to make canvas and ropes for sailing ships. In around 1830, at the industry's peak, some 173,000 hectares were farmed.
But the rise of synthetic materials in the mid-20th century made the fibre less attractive.
As did the United States. As part of its war on drugs – and efforts to protect its cotton industry from competition – hemp farming in the US got caught up in anti-marijuana legislation and was effectively banned. An infamous propaganda campaign assimilating hemp with drugs referred to "the burning weed with its roots in hell".
In fact hemp is low in tetrahydrocannabinol (THC) – the substance that gives you a high – and THC levels for industrially farmed hemp cannot exceed 0.3 percent.
By the 1970s, hemp farming had been banned in most countries around the world.
While production in France slumped to just 300 hectares, for use in paper making in the Aube region, it managed to hang onto its savoir-faire.
Listen to a report on hemp farming in Aulnoy on the Spotlight on France podcast:
The return
The French always knew that hemp was feisty. And its ability to resist big changes in temperature and handle drought has spurred its return as a crop well adapted to global warming.
Hemp production has tripled here over the last decade to reach 24,000 hectares, making France the world’s third-largest producer after the US and China, and leader in Europe, where it accounts for more than a third of the EU’s production.
"We now have 1,550 farmers nationwide and it's a fast-growing sector," says Franck Barbier, head of the professional body InterChanvre that represents hemp growers.
Barbier had a background in agro-business but moved into hemp a decade ago, convinced it was a good crop for agriculture, the environment and the economy.
For a start it’s one of the world’s fastest-growing plants. "It can grow up to three metres in just five months, and around 10 centimetres a day in the month of June," Barbier explains as he strides through a 10-hectare field in Aulnoy, 60km east of Paris.
The plant's dense canopy deprives weeds of light, thereby reducing reliance on pesticides.
"It doesn’t need any products to control disease or pests – no weedkillers, fungicides or insecticides. So it’s good for farmers to no longer have to use such products," he says.
And thanks to the plant's powerful root system, it can delve two metres underground to fetch water, allowing it to grow throughout drier summer months without the need for irrigation.
Crucially, hemp is a good carbon sink – one hectare of hemp can sequester up to 15 tonnes of CO2 in its stems, Barbier says.
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No waste
Everything in the hemp plant is useful. The protein-rich seeds are hulled to produce foodstuffs and oil for cosmetics, while whole seeds can be used in animal feed.
The tough stalks are processed in hemp mills where the fibrous outer layer is separated from the inner core, known as hurds.
Hemp fibre is used to make paper and textiles. And as a lightweight, durable substitute for plastic, it's increasingly used in car manufacturing.
But it’s perhaps in the construction industry that "green gold" – as it’s sometimes called in France – is making the biggest strides.
With the construction sector responsible for some 40 percent of energy consumption worldwide and 36 percent of the greenhouse gas emissions that contribute to global warming, hemp's ability to lock in CO2 makes it a key player in the fight against climate change.
Both fibre and hurds are used in the construction industry, whether in "hempcrete" – a mixture of lime, hemp hurds and water – hemp wool, or fibre-board insulation.
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Greener buildings
When the mayor of Trilport, Jean-Michel Morer, began looking for ways of making more sustainable social housing in his town a decade ago, he turned to the nearby PlaneteChanvre hemp mill.
"The carbon footprint is remarkably low because the hemp is grown locally, just 13 kilometres away, it hasn't been transformed, just rendered on the walls with water and lime," he says, pointing to a block of flats insulated with a layer of hempcrete on the outside.
"It's a first in terms of bio-sourced materials for a three-story building. And it's energy-saving," he explains. "Some residents haven’t turned on the heating since they moved in nearly two years ago.
"But the real difference is in the summer – when it's hot, the buildings stay cool," he says, reducing the need for energy-guzzling air conditioning.
For the primary school's new 1,000-metre square canteen and recreation area, Morer called on local firm Wall’Up Préfa, which makes prefabricated walls entirely from hempcrete.
The new gas-fired boiler room also has walls made of hemp. "We obtained certification to show that it can resist fire for more than four hours," the mayor says proudly.
Morer's promotion of hemp in public utilities has put Trilport on the map. "Using local businesses, local employees and locally sourced products has allowed us to really build a circular economy."
And that's key to more sustainable development.
"Lots of people talk about the environment but we're taking concrete measures," says the mayor. "Using hemp makes farming more respectful of the ecosystem, it's less polluting of our water supply and farmland, it uses less water and allows us to insulate buildings more easily and with fewer risks to health."
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Getting more farmers on board
Only 0.3 percent of farmers in France grow hemp today but faced with the mounting demand for hemp in textiles, plastics and insulation, Barbier says the industry plans to "double production over the next five years".
InterChanvre is working hard to try and get more farmers on board.
The sector has invested nearly €100 million over the past five years to increase the number of hemp mills from just seven at present to make sure farmers’ crops can be processed as locally as possible.
Barbier says hemp is of interest as a rotational crop since its ability to regenerate the soil means it can increase yields of winter wheat "by around 8 percent".
While the machinery needed for harvesting involves a hefty investment and revenues are lower than for wheat and other cereals, companies like Wall'Up Prépa, convinced of hemp's bright future, are paying more to farmers to secure supplies.
Under the EU’s Common Agricultural Policy (CAP), hemp farmers can claim subsidies of around 80 euros per hectare – a measure currently available in France, Romania and Poland.
Meanwhile, InterChanvre is pushing for hemp to fall under the Payments for Ecosystem Services (PES) programme, which would allow farmers to benefit from EU subsidies of "at least €200 per hectare", Barbier says.
In the meantime, he points to foreign interest in tapping in to France's know-how.
"Given hemp's environmental benefits, Germany, Spain and several Eastern European countries are already seeking France's expertise in transforming hemp to develop their own industries."
This story was produced as part of the Spotlight on France podcast, episode 114.
