A guide to fabrics: what is a sustainable fabric?

Defining a sustainable fabric is surprisingly difficult. Fabric can be made from plant fibers, animal proteins, or fossil fuels. The latter is obviously the least sustainable. But the processes of turning fiber into fabric and dyeing it raise additional issues for sustainability—both environmental and social sustainability. 

To begin with, a sustainable fabric should be a natural fiber grown sustainably. Natural fibers include cotton, flax, bamboo, hemp, jute, wool, and silk. 

When we think of synthetic fabrics, we think first of polyester and nylon. These are plastics, and plastics create too many environmental issues to count as sustainable. But at least one new fabric comes from dairy waste. 

Nowadays, much of our clothing comes from fabric blends. A blend of, say, cotton and polyester or wool and nylon, further complicates questions of sustainability. It might be more sustainable than one component and less sustainable than another. 

Issues for fabric sustainability

But turning natural fibers into fabric often requires various toxic chemicals. Some natural fibers become various kinds of rayon. Rayon is not a synthetic fabric like polyester, but it’s no longer quite a natural fiber, either. It’s popular in part because it’s very soft. 

Unfortunately, making really soft cotton requires comparable chemicals. Some of these chemicals can remain on the clothes when you get them home from the store. 

And no one wears only fabric with its natural color. The dyeing process likewise affects the environment. Many fabric dyes contain toxic chemicals that present all the same problems to textile workers, the water supply, and our skin.

Many factories take care to handle all these chemicals safely and dispose of them properly. But too many endanger their workers and then dump used chemicals into the water supply. Also, every process in manufacturing and transporting clothing requires a lot of energy. Companies vary in their willingness to promote energy efficiency. 

Finally, social sustainability requires paying workers well, not relying on child labor, and providing a safe working environment. It’s a safe bet that really inexpensive clothing has been produced by companies and processes that exploit and endanger workers. 

Fast fashion violates both environmental and social sustainability. Buy anything else to be eco-friendly. Discerning consumers can look for certification of environmental best practices and fair trade. These products will cost more but be of much higher quality and last longer. 

Here are some sustainable fabrics:

Organic cotton

The clothing industry uses more cotton than any other natural fabric. Unfortunately, conventional cotton presents many environmental problems. It’s usually grown as a soil-depleting monoculture.  Growing it requires 10% of all the pesticides used in agriculture. Not to mention the 2,600 gallons of water required to produce one pound of cotton. 

Organic cotton, by definition, doesn’t use synthetic herbicides, pesticides, or fertilizers. It also depends on crop rotation, which keeps the soil healthy. Organic cotton requires less water than conventional cotton. Much of it is picked by hand instead of with heavy machinery. 

But natural herbicides and pesticides are still toxic and can endanger the health of farm workers. Plus, organic farming requires considerably more land to achieve the same yield as conventional farming. 

Growing organic cotton is much more sustainable than conventional cotton but less so than other natural plant fibers. You can buy organic cotton with confidence, though. 

Linen

Linen comes from flax, specifically the woody interior of its stems, called bast fiber. All the other parts of the flax plant have other uses, so nothing goes to waste. Flax grows quickly and is ready for harvest in about three months.

Traditionally, after harvest workers would soak the plants in water for a week or two in a process called retting. Retting enabled separation of the bast fiber from the stems. 

Nowadays, however, manufacturers often use various chemicals to speed up the process. The traditional labor-intensive processes create a more sustainable fabric but also result in a more expensive product. 

Making linen from flax involves combing it, spinning it into yarn, and weaving it into fabric. 

Linen fabric dries more quickly than cotton, which makes it valuable for clothing in hot and humid climates. It is a strong fabric that lasts a long time, but it wrinkles easily. Also, it’s not an especially soft fabric, although it does soften over time. 

Bamboo

Bamboo is a type of grass. It grows very rapidly from an underground rhizome. It requires little attention while growing and needs little irrigation, fertilizer, or pesticides. Because it grows from a rhizome, harvesting bamboo doesn’t kill the plant. A new culm will grow to replace the old one. 

An acre of bamboo produces about ten times as much fiber as an acre of cotton. 

Growing bamboo is very sustainable. Bamboo fabric is somewhat controversial. It can be retted like flax to make a bamboo linen, but most bamboo fabric is bamboo rayon. Many critics deny that bamboo rayon can be a sustainable fabric, but they haven’t compared it with other alternatives. Growing bamboo is more sustainable than growing cotton. Even organic cotton fabric is made with harsh chemicals.

Rayon not otherwise specified is made from wood. The basic manufacturing process is the same in either case. Making rayon requires dissolving the fibers in harsh chemicals to yield a pulpy mass much more quickly than the retting process. But instead of combing and spinning it to make a yarn, this goo gets extruded through a spinneret. No natural fiber remains. After extrusion, the fibers require another chemical bath to harden it into thread. 

Rayon comes in different varieties, depending on specific manufacturing techniques. The most common is called viscose. Newer techniques such as modal or lyocell are considered more environmentally friendly. 

Formerly, manufacturers of any product simply discharged used chemicals into the nearest waterway. Now, most of them try to recover and reuse their chemicals. Rayon is no longer an environmental disaster, but it’s not yet sustainable, either. 

Most bamboo is grown in China. Among other problems, it must travel long distances to make it to the US. The method of travel greatly affects sustainability. Ocean transport has much less environmental impact than air transport. 

Hemp

Hemp and marijuana come from different strains of the plant Cannabis sativa. When marijuana became illegal in the US, it essentially destroyed growing of industrial hemp. Only since 2018 has it resumed. Hemp fabric, therefore, has only recently become available. 

Hemp can grow in contaminated soil and can even restore it. It grows quickly and is ready to harvest in three or four months. Not only that, but it grows so large that it crowds out weeds. It needs no herbicides. And since it’s naturally resistant to insects, it doesn’t need pesticides, either.

Both bamboo and hemp grow best in tropical or semitropical climates. Right now, China supplies much of the world’s hemp. But hemp can grow in cooler climates than bamboo. In fact, until about 1937, industrial hemp was grown throughout much of the US. Once American production ramps up, hemp will not have the geopolitical problems or the transportation costs of bamboo. 

Like flax, hemp provides bast fiber that is processed the same ways. Like bamboo, it can be made either into linen or rayon. So far, most commercially available hemp fabric is linen. The American public generally prefers the soft feel of rayon. 

Jute

Jute follows only cotton as the most-produced plant fiber, but it is little-used for clothing these days. Most of it now comes from the Indian subcontinent. Most production follows the same manual techniques used for centuries. 

The jute plant grows to more than ten feet high and provides bast fiber. After retting, its fibers are among the longest of any natural fabric. They’re also very rough. The familiar burlap bags are made from jute. It has other industrial applications as well. In the home, it’s likely to be used for upholstery, carpeting, curtains, or canvas. 

Few people want to wear jute clothing next to their skin, but sweaters and light jackets made of jute are becoming more popular worldwide. It’s probably possible to make a jute rayon, but to my knowledge no one does. Anyone who views rayon with suspicion as a sustainable fabric should approve of jute.  

Wool

Wool comes from the fur of certain animals: mostly sheep but also alpaca, cashmere goats, camels, or yaks. Sheep, among other animals, require shearing, or cutting off the fur manually. Some of these animals naturally shed, so obtaining the raw wool is fairly simple. 

Each individual animal produces different kinds of fiber, so it is necessary for someone to class the wool into different categories. Then it undergoes various cleaning procedures.

Cleaned wool is then carded, spun, woven, and dyed like the plant fibers.

Silk

Silkworms grow and feed on mulberry trees. The trees require a lot of water and grow best in controlled temperatures. This part of the process of making silk has the greatest environmental impact. On the other hand, any pesticides would kill the silkworms and thus defeat the purpose. 

Silk itself comes from the cocoon the silkworm produces. Left to itself, the worm would become a moth, but its emergence would destroy the filament. Therefore, the cocoons are steamed to kill the larva. Each cocoon comprises a continuous filament with a usable length of up to 3,000 feet! Each one is too thin to use, so it is necessary to twist several strands together.

Qmilk

Milk, like hair, is a protein and therefore suitable for making yarn. Attempts to make fabric from milk began in the 1930s. Qmilk is made from casein, a waste byproduct of the dairy industry. It was only introduced in about 2011. As a patented product, only one manufacturer makes it. As such, it is not likely to be a major player in the fashion industry anytime soon.

Unlike other synthetic fabrics, Qmilk is completely biodegradable and compostable. It requires very little water and none of the chemicals used for rayon or synthetics. What’s more, it’s flame retardant and very smooth in texture. All the manufacturing processes are designed with sustainability in mind. 

Even vegans, many of whom deny that anything made from animal products can be sustainable, look on Qmilk as a sustainable fabric.

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