«Nettle could be the replacement for synthetic fibers since it is the most stable fibre in the natural fibres range»
Urtica Dioica – a Europe-native herbaceous perennial flowering plan
The panorama of natural and sustainable fibres has widened in the last few years; rediscovering old and traditional materials that have been neglected for cotton or synthetic fibers. The rising focus on sustainability and fashion industry bringing back the attention to these fibres, proved them to be an excellent solution to decrease cotton and artificial materials, such as polyester or viscose. One of these fibres is nettle, also known as stinging nettle or Urtica Dioica, a Europe-native herbaceous perennial flowering plant; usually, nettle fabrics are made with the Himalayan Nettle, or Girardinia Diversifolia. Because, since these two varieties are biologically similar, their fibres are quite different.
Nettle fibres excellent tensile properties
Himalayan nettle – also known as Ramie – is shiny on the surface. It has the longest thread currently known, and, once spun, is finer yet more robust and more elastic than linen. It’s not that durable though. Since the interest toward sustainable fibres and cotton alternatives grew in Western countries; many farmers and producers in Germany started growing nettle, which proved highly versatile and characterized by fineness and flexibility.
Nettle fibres have also excellent tensile properties due to the cellulose volume fraction. Also the highest tensile strength of 40 – 50 cN/tex of all-natural fibres. In comparison, cotton is 16 to 17, linen 20 to 23, hemp 22 to 30, and polyester 60 cN/tex. Unlike hemp fibres, there is no legal issue with the cultivation of nettles, which has made the plant a viable and legal crop. Like hemp, nettles also use much less water and no pesticides to grow compared to cotton. They are perennial – which means they can be harvested every year – and have a high growth rate, making it a quickly renewable resource.
NFC GmbH Nettle Fibre Company processing stinging nettle
Because of its qualities, the demand for nettle yarn is constantly increasing; proving how this material is perfect to «replace synthetic fabrics. Since it is the most stable fiber in the natural fibres range», states Dr. Heiko Beckhaus, President of NFC GmbH Nettle Fibre Company. On the other hand, compared to other domestic fibre plants, the degree of the fibre content of nettle, which is around ten percent, is small, and the decortication is more complicated. There is a growing concern over the damage to the environment caused by producing synthetic fibers and growing non-organic cotton for fast fashion. There is a trend though for stinging nettle fibres, for its use in ecologically friendly fabrics.
This encouraged researches and advances in spinning technologies; as well as cross-breeding to produce the best high-fiber yielding nettle plants. As Beckhaus explains, he has been able to agriculture a new generation of nettle with 20% degree of fiber content. Working «in collaboration with german farmers, the Leibniz-Institut für Agrartechnik und Bioökonomie; the Faserinstitut Bremen; the 3N Kompetenzzentrum Niedersachsen Netzwerk Nachwachsende Rohstoffe und Bioökonomie; and the Institut für Pflanzenkultur and other companies». The use of nettle for fabrics, it’s not a recent discovery. The textile application of fibre from stinging nettle dates back to at least 3.000 years ago. But after World War II, the natural fibres were replaced by cotton, which was easier to work with and less expensive, even if more harmful for the environment.
Urtica Dioica, nettle fibre as a substitute of silk
The rediscovery of nettle is not only because it is a sustainable and renewable source but also because it can be a good fit for the luxury and fashion industry, thanks to its appearance. As Beckhaus explains, «Urtica Dioica is shiny, and it’s similar to the finest silks; it is even better than silk since because of its structure it is more breathable». Nettle is the most transpirant of all other natural fibres thanks to its porous core fiber, making it breathing much better than flax or linen which are more likely fibre bundles.
For example, elementary nettle fibres are hollow and got open pores, which creates natural breathability. Considering that silk is one of the most polluting materials, replacing it with nettle is an interesting and eco-friendly option for the luxury industry; according to the Higg Index, in fact, silk has the worst impact on the environment of any textile, including polyester, viscose/rayon, and lyocell. It’s worse than cotton, using more freshwater, causing more water pollution, and emitting more greenhouse gases, not to mention animal welfare, since to make silk, larvae are killed by steaming before they eat through the silk cocoon.
The issue of ligning when talking about nettle stiffness: NFC solution
Given these factors, nettle can be a sustainable solution for the fabric industry, not only for the nature of the crops themselves that do not need pesticides to grow but also because of the mechanical processes involved. «The decortication process to which nettle undergoes is 100% mechanical, and it doesn’t involve any chemicals or pesticides. We are GOTS certified, and we can keep an outstanding CO2 balance during the whole journey». Thanks to its nature, nettle processing cuts down on chemicals, energy, machinery, and pollution that are often involved in producing other materials.
The only challenge starts at the point in which producers have to take the lignin off. Lignin is a class of complex organic polymers. These form crucial structural materials in the support tissues of most plants, including nettle. Because of its stiffness, producers of nettle yarns need to wash or take the lignin off the fibers. Many producers, mostly in southeast Asia use enzymes.
«Living creatures who eat the lignin out. Controlling how much lignin is eaten can become problematic». Nettle fibers need to keep a small percentage of lignin that holds the fibre stable. «At NFC we needed a way to perform this process without any chemicals. We use a boiling under pressure, adding a tenside or detergent». Like citric acid came into play as a non-chemical and not polluting replacement of phosphoric acid, proving to have moderate acute and chronic toxicity to aquatic life in waters.
Urtica Dioica: a versatile material
Using natural fibres and mechanical and chemical-free processes is environmentally friendly, but there is always the waste problem to face. When asked about this issue, Beckhaus is optimistic: «we do not have any waste, we only have products. The leaves stay on the ground as fertilizers, and we use the shorter fibers, which are around twenty-five percent, shives, and other side products that can be processed into top-quality useful products. The shives the small wooden pieces – are used to produce non-flammable wooden elements (chipboards, doors, coverings, furniture or construction material) have been experimentally created in cooperation with an innovative enterprise».
Nettle is a versatile material, and it can be mixed with other fibers to obtain different blends, depending on the needs; as Beckhaus explains: «we often bled nettle with twenty-five percent hemp and fifty percent cotton, but we also worked on 100% nettle yarn which is perfect for nightgowns and haute couture industry. Nettle yarn is exclusive because it’s expensive and hard to spin. You need to know how to work with it». When asked about the sustainability of their approach, Beckhaus is confident «We are a no-waste company, all our products (which also include hemp) are renewable, and there are no microplastics or chemicals involved. Manufacturing of our natural fibres does not utilize any pesticides and consumes only little water».
Dr. Heiko Beckhaus
Is President of NFC GmbH Nettle Fibre Company, founded in August 2011. Originally the purpose of the enterprise was solely the decortication of nettle straw to market nettle fibres for the textile industry. Nowadays, they are capable to process bast fibre plants such as flax, hemp, stinging-nettle, oilseed-flax, kenaf, and Ramie.
