Hemp, or industrial hemp, is a variety of the Cannabis sativa plant species that is grown specifically for industrial use. It can be used to make a wide range of products. Along with bamboo, hemp is one of the fastest growing plants on Earth. It was also one of the first plants to be spun into usable fibre. It can be refined into a variety of commercial items, including paper, rope, textiles, clothing, biodegradable plastics, paint, insulation, biofuel, food, and animal feed.
Although cannabis as a drug and industrial hemp both derive from the species Cannabis sativa and contain the psychoactive component tetrahydrocannabinol (THC), they are distinct strains with unique phytochemical compositions and uses. Hemp has lower concentrations of THC and may have higher concentrations of cannabidiol (CBD), which decreases or eliminates its psychoactive effects. The legality of industrial hemp varies widely between countries. Some governments regulate the concentration of THC and permit only hemp that is bred with an especially low THC content.
In 2020, the United Nations recommendation to explicitly remove international control from hemp products containing predominantly cannabidiol and not more than 0.2% of THC was rejected by a majority of votes, meaning that hemp and extracts thereof will remain in some legal ambiguity under the current UN conventions.
Hemp is used to make a variety of commercial and industrial products, including rope, textiles, clothing, shoes, food, paper, bioplastics, insulation, and biofuel. The bast fibres can be used to make textiles that are 100% hemp, but they are commonly blended with other fibres, such as flax, cotton or silk, as well as virgin and recycled polyester, to make woven fabrics for apparel and furnishings. The inner two fibres of the plant are woodier and typically have industrial applications, such as mulch, animal bedding, and litter. When oxidized (often erroneously referred to as "drying"), hemp oil from the seeds becomes solid and can be used in the manufacture of oil-based paints, in creams as a moisturizing agent, for cooking, and in plastics. Hemp seeds have been used in bird feed mix as well. A survey in 2003 showed that more than 95% of hemp seed sold in the European Union was used in animal and bird feed.
Hemp is classified under the green category of building design, primarily due to its positive effects on the environment. A few of its benefits include but are not limited to the suppression of weed growth, anti-erosion, reclamation properties, and the ability to drain soil from poisonous substances and heavy metals.
The use of hemp is beginning to gain popularity alongside other natural materials. This is because cannabis processing is done mechanically with minimal harmful effects on the environment. A part of what makes hemp sustainable is its minimal water usage and unreliability on pesticides for proper growth. It is recyclable, non-toxic, and biodegradable, making hemp a popular choice in green building construction.
Hemp fibre is known to have high strength and durability and has been known to be a good protector against vermin. The fibre has the capability to reinforce structures by embossing threads and cannabis shavers. Hemp has been involved more recently in the building industry, producing building construction materials including insulation, hempcrete, and varnishes
Hemp made materials have low embodied energy. The plant has the ability to absorb large amounts of CO2, providing air quality, thermal balance, creating a positive environmental impact.
Hemp’s properties allow mold resistance, and its porous materiality makes the building materials made of it breathable. In addition hemp possesses the ability to absorb and release moisture without deteriorating. Hemp can be non-flammable if mixed with lime and could be applied on numerous aspects of the building (wall, roofs, etc.) due to its lightweight properties.