Bamboo Clothing: Green, or Greenwashed?
If you’re looking for more eco-friendly clothing, should you choose bamboo?
Bamboo has been touted for the last several years as being one of the most environmentally-responsible fabrics on the market. A hardy grass, it grows like a proverbial weed, sometimes sprouting 4 feet in a single day – and that’s without the assistance of pesticides, herbicides or fertilizers let alone irrigation. Bamboo sounds like the kind of “green” fabric you’d love to love – were it not for the process needed to transform it from a plant into something like a pair of socks.
In August 2009, the U.S. Federal Trade Commission issued "Have You Been Bamboozled by Bamboo Fabrics?" a report that questioned the fiber’s green bonafides. While not challenging how the grass is grown, the FTC warned that transforming the plant’s tenacious stalks into soft fabrics requires the use of toxic chemicals that pollute the air and water,” reducing the cloth’s natural appeal. Many consumers have been wondering ever since if bamboo is green – or being greenwashed.
What concerns the FTC is the manufacturing process. Because bamboo is so hardy, it is also hard to refine into fiber – unless a manufacturer uses toxic chemicals like sodium hydroxide, which can cause chemical burns or blindness, to break down bamboo’s cells into something pliable called viscose.
Some manufacturers claim that sodium hydroxide poses no health hazard if used and disposed of properly. I’m more reassured by companies that use fabric from bamboo which has not only been certified as organically grown, but where the chemicals used in processing bamboo into viscose are captured in a “closed loop” system that is supposed to prevent them from being released into the environment. The resulting viscose is Oeko Tex 100 certified, which means that no harmful substances lurk in the finished textile, where they might rub off on your skin. Conventionally produced and polluting "bamboo" might be labelled simply bamboo, or rayon from bamboo. You can get a more comprehensive explanation on the entire process, and the controvery surrounding the selling of bamboo, here.
Organic cotton is superior to bamboo. But If you’re choosing between conventionally grown cotton and bamboo, given what I can figure out about the growing and processing of both, I would choose bamboo. (Most cotton in use today is not organic.)
Cotton is more vulnerable to bugs and disease than almost any other crop grown, so much so that it demands 22.5% of the world’s pesticide use . Unless cotton has been certified organic, in all likelihood, it has probably been sprayed intensely with pesticides. Be alert: "Natural" cotton means nothing. If you prefer cotton, it should be certified organic.
Bamboo requires little if any pesticide to grow.
Cotton is considered a renewable resource – it takes about 3 months to grow, but needs to be replanted and harvested every year, which would make it very energy-intensive to grow.
Bamboo is considered a rapidly renewable resource. Once planted, it can take between three and seven years to reach maturity, depending on the species. But thereafter, the plant continues to grow, as only the top stalks are harvested, not the roots (if you’ve ever tried to eradicate bamboo from your yard, you’ll know the story – it grows and grows and grows…).
Climate Change Impact:
I haven’t been able to find any information that compares the energy costs of producing cotton fabric to bamboo fabric. However, BambooNow.com says bamboo “is one of the most effective scrubbers of carbon dioxide in the world. It grows four times faster than wood, produces far more biomass, and sequesters 35% more C02.”
The general steps in processing both cotton and bamboo are very similar. They include: spinning (transform the processed plant threads into yarn), weaving (yarn into fabric), dyeing , and some kind of finish (for example, a chemical finish may be applied to make the fabric “wrinkle resistant”). Finally the fabric is cut and sewn into the desired product. Both fabrics have a global life cycle, with most bamboo being grown and processed in China, most cotton being grown in China and other countries in Asia, and manufacturing taking place in still other countries. Dyeing either cotton or bamboo can have equally harmful or harmless consequences, depending on the kinds of dyes used.
By the end of production, it will have taken about 700 gallons of water to make a cotton t-shirt; a t-shirt made from bamboo would use about 35 gallons. Cotton is one of agriculture’s thirstiest cultivated plants, requiring 101 gallons of water to create a pound of finished cotton.
Manufacturers claim that bamboo has natural anti-bacterial properties which help repel body odor, meaning you should be able to wash it less frequently than other materials. Manufacturers also claim that bamboo dries faster than cotton, possibly reducing dryer use (which is not recommended anyway, as bamboo will retain its shape better if line dried). The FTC has dismissed the anti-bacterial claims; if you are line-drying both cotton and bamboo, it shouldn't matter too much which one dries quickest. One benefit I can personally attest to since I use bamboo towels, is that bamboo seems to be more absorbent than cotton, thus reducing the number of towels needed after a shower or bath.
What about the greenwashing?
One way manufacturers greenwash their products is by touting bamboo on the label - even if only 5% of the product contains bamboo fiber. Consumers might see the word and believe that the entire piece of clothing is bamboo, when only a fraction of it comes from bamboo. Don't pay a premium for what you think is 100% bamboo if the fiber has only been added to spruce up a company's marketing campaign.
As for cotton, don't be seduced by the words "natural" cotton. In all likelihood, cotton grown "naturally" has been showered with pesticides and herbicides in the course of its lifetime. If you're buying cotton new, choose organic.
In a future post, we’ll report on hemp and recycled polyester. We'll also tackle TENCEL Lyocel, which processes wood into fiber using the closed-loop method to capture the polluting chemicals.
Meanwhile, you can read about more eco-friendly options at this month’s Green Moms Carnival.
Thanks to research assistant Tracy Gaudet for help with this article.