Hemp – the sustainable crop for the environment & climate

In earlier times widely cultivated and used, its cultivation was temporarily banned. Today, hemp is slowly returning to our fields and into our consciousness. Currently, 58 certified industrial hemp varieties in the EU may again be cultivated by farmers under certain conditions, as the content of psychoactive THC in the flowers is certainly below 0.2%, thus excluding substance abuse. However, in most European countries, hemp still leads a shadowy existence. France is the clear leader in hemp cultivation, where in 2017 over 17,000 hectares of agricultural land were used for hemp, in contrast to Germany and Austria with only 1,600 hectares and 1,500 hectares, respectively. In light of its versatile uses and against the backdrop of pressing questions about how our agriculture can be made more environmentally friendly, sustainable, and climate-friendly, we should literally give hemp more space again! It's worth taking a closer look.

Hemp in Organic Farming: Advantages for Farmers

Hemp can essentially grow almost anywhere, as it does not have special requirements for the location. However, to achieve higher yields of seeds and fibers, deep, humus-rich, calcareous, and nutrient-rich soils with regulated water supply and a pH value in the neutral to slightly alkaline range are necessary. It copes well with our temperatures and can also tolerate light frost.

Hemp Against Weeds, Pests & for Healthy Crop Rotations

The hemp seeds germinate quickly after sowing and cover the ground, so that only little weeds can grow. For fiber production, it is sown very densely, so that the plants can grow up to 4 meters high in a short time and branch little, thus usually requiring no weed control. To harvest seeds, the row spacing between the plants must be larger, as they spread out, bloom profusely, and thus form many seeds, which may require mechanical weed control.

Fertilization for a Good Nutrient Utilizer

It cannot be done without. About 80-100 kg of nitrogen per hectare is needed if one wants to achieve profitable yields of fibers and seeds. Hemp utilizes organic fertilization with manure and dung very well, as the slow release of nitrogen corresponds to its temporal nutrient needs. Additionally, thanks to its roots, which can grow up to three meters long, it supplies itself with nutrients and water from deeper soil layers!

Advantages of Hemp Cultivation for Soil, Climate & Agriculture

Since the hemp plant is very robust, the use of chemical agents against pests and fungal diseases can practically be dispensed with. A significant plus for the environment, especially in times of bee and insect decline. Hemp does not have any special requirements for the preceding crop. Clover grass or legumes are suitable, as they are natural nitrogen binders, from which the hemp plants can benefit. Hemp itself is a good preceding crop because weeds cannot thrive in its company. With its deep and widely branched roots, it loosens the soil, creating a good climate for soil organisms and facilitating the growth of subsequent plants.

Sustainable Uses of the Hemp Plant

Aside from its medicinal and cosmetically valuable ingredients, the entire plant is actually usable for us: Hemp seeds are a nutritious crunchy snack, provide a high-quality cooking oil, and can be used in various ways as a protein-rich powder and hemp flour after pressing. With the flowers and leaves, we enjoy a soothing relaxing tea, and the fibers can be processed not only into high-quality textiles but also into many other materials such as paper, ropes, or composite materials. Even the woody parts can still be meaningfully used as bedding or in building and insulation materials.

Paper: Hemp Instead of Wood

Paper has been made from the fast-growing, soil and forest-conserving raw material hemp for over 2000 years! Until the late 19th century, up to 90% of the paper produced worldwide was made from hemp fibers; today, it is only a vanishingly small 0.05%! Since the industrial production of hemp paper has not been promoted and developed, the production costs are currently still unprofitably high. In terms of the same amount of paper produced, hemp requires only a quarter of the agricultural area compared to trees. Hemp plants can also be cultivated on a small scale and in almost all climates. In this regard, hemp, as an annual plant, produces four to five times more paper on the same area than a forest. In wood, the approximately 50% cellulose content is bound by 25% lignin. To produce paper, the lignin must be dissolved with large amounts of environmentally harmful and sometimes highly toxic chemicals such as sulfur salts. In contrast, in hemp, the approximately 35% cellulose in the fiber and another 35% in the wood content is bound with only about 3% lignin, so that the extraction requires significantly fewer chemicals. Due to the high cellulose content, hemp paper is extremely durable, remains tear-resistant even in a damp state, and can be recycled up to seven times largely without loss of quality, unlike wood, which can be recycled about three times. Hemp paper does not yellow because it is acid-free and does not need to be bleached with chlorine, which heavily burdens soils and groundwater.

Building: Houses Made of Hemp & Hempcrete

The use as a sustainable building material is probably one of the most forward-looking uses of the hemp plant. A company in England has already developed "Hempcrete," a not only stronger but also much lighter and above all more environmentally friendly alternative to conventional concrete. There seems to be great potential here. For insulation, hemp can be used as insulation felt or mats together with supporting fibers made of polyester and the addition of boron salt for fire protection improvement – suitable for allergy sufferers, moisture-resistant, and pest-resistant without chemical treatment. More on this topic here in the blog.

Plastics: Biodegradable & Robust

Henry Ford recognized the potential of the hemp plant as early as the early 1940s with the almost completely compostable prototype of his Ford model, making his car almost exclusively from soy and hemp plastics. Even today, hemp plastics are in demand in the automotive industry. Their natural resistance to harmful fungi and their poor flammability are appreciated. Form-pressed parts made from hemp also have less sharp breaking edges compared to other materials, thus posing a lower risk of injury. They are significantly lighter than wood fibers, and lighter cars consume less energy.

Textiles: Hemp Fibers & Fashion

Even Christopher Columbus set sail with sails made of hemp, and until the middle of the 19th century, hemp was the most commonly used textile fiber in the world alongside flax, before being replaced by the cheaply produced cotton.
Today, hemp textiles are experiencing a welcome comeback – thanks to the unique properties of the hemp fiber, they combine elegance, variety, and skin compatibility with robust functionality, durability, and high wearing comfort. They keep warm in winter and cool in summer, are dirt-repellent, and more tear-resistant than cotton. Hemp clothing can absorb up to 30% moisture without sticking to the skin and developing odors. New designs from innovative manufacturers show that hemp also has a bright future on the catwalks of fashion metropolises.

Hemp as a Natural CO₂ Sink

Together with other plants, hemp can sustainably counteract climate change – not as the solution, but as an important part of a comprehensive strategy that must focus on preserving biodiversity. Like many other crops, such as soybeans, rice, wheat, and sugarcane, the hemp plant binds CO2 from the atmosphere during its growth. While it cannot compete with the potential of large old trees, it is generally not burned or subjected to other processes that release the bound CO2 again.

Sources:

Schluttenhofer C., Trends Plant Sci. 2017 Nov;22(11):917-929. doi: 10.1016/j.tplants.2017.08.004. Epub 2017 Sep 5.
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