Is silk sustainable?

Silk. I love it – it’s soft, unique and natural.

But it also bothers me. Part of me thinks it’s better than synthetics, but I’ve also heard that it’s bad, though I can’t remember why.

It’s time to worm out some truths.

Where does silk come from?

Most silk fabric is made from the cocoons of farmed silk worms, Bombyx mori, which eat mulberry leaves. Tragically a female silk worm lays up to 400 eggs in one go and then dies.

Larvae hatch from the eggs two weeks later, feast on mulberry leaves and produce liquid raw silk from its saliva. The silk hardens and the baby silk worms – pupae – winds it around itself in a cocoon.

In the wild the pupae grows into a moth and hatches, but not these ones. Silk farmers boil, gas or steam the whole cocoon – pupae included.

Silk threads are then pulled from the cocoons and later cleaned with bleach.

It takes up to 3,000 cocoons to make half a kilo of silk thread.

Where is silk made? 

China produces most of the world’s silk. India also has a large silk industry, followed by other smaller Asian countries.

There’s nothing cottage about mainstream silk. It’s big business and large companies invest in growing and selling silkworms to manufacturers.

When silk loses its shine

Silk can be just as ugly as the conventional cotton industry – just look at humanitarian photographer Lisa Kristine’s pics of silk dyeing in India.

Before she founded Bhumi Organic Vinita Baravka worked in international health visiting rural communities in India and Bangladesh where silk is made and processed.

“Child labour is rife in this industry with many children and workers suffering injuries from boiling water, scalding and infections from burns,” Vinita told Sustainable Shopper.

“The silk dyeing process – like most textiles – includes toxic dyes and all that that entails (fumes and poisoning).”

Peace silk

A smaller industry called peace silk harvests the silk threads after the moth has hatched. It’s a more difficult process and produces a less reliable quality thread and the end product has a different look and feel.

Some critics argue that because peace silk is farmed, it still results in mortalities. It produces byproducts of embryos or hatchlings and, given the moth lays so many eggs, it’s not possible to feed so many so eggs are destroyed or hatchlings starve to death.

Wild silk 

If this all paints a hopeless picture of sustainability, hang in there.

eri silk sustainable silk

Eri moth. Courtesy

Meet the eri worm.  This silk worm isn’t domesticated like the common Bombyx mori and it feeds on castor oil plants. Harvesters take silk from disused cocoons in the wild.

Silk from eri worms is processed in northern India and parts of China and Japan. Its silk is heavier and darker, lending it to blend well with cotton and wool.

Internationally recognised Perth designer Zuhal Kuvan-Mills from Green Embassy used eri silk to make her latest collection of elegant, ethereal, haute couture pieces.

Silk isn’t vegan 

Silk is a protein fibre, like wool and since it comes from worms, it can’t be called a vegan product – vegetarian maybe but not vegan.

Can you get organic silk?

Organic certification schemes have strict environmental and social requirements.

The Global Organic Textile Standard, GOTS, is an internationally reputable certification written for processing natural textiles. It accredits 3,600 facilities around the world, mostly cotton businesses, but it also certifies companies manufacturing and retailing silk.

GOTS bans hazardous chemical dyes and child labour and it has strict requirements for waste water treatment.

Which uses more energy – silk or cotton?

Generally speaking most silk is hand harvested and processed – whereas the growing, production and processing of majority of the world’s cotton is mechanical so it uses far more energy and fuel to produce.

Eri silk is one of the least energy intensive textiles you can buy.

Is silk sustainable?

The majority of conventional silk isn’t sustainable. It might be a natural fibre, but it aint eco.

While mulberry trees and silk worms are plentiful because they’re farmed, the harsh chemicals used to process silk is damaging to workers and the environment. It’s also arguably an inhumane way of producing textiles compared to other natural fibres – however wool is debatable!

Fortunately organic, wild harvested eri silk is sustainable. Fairtrade doesn’t certify silk farmers so if you’re looking for evidence of third party checks on worker conditions, look for the GOTS logo which has environmental and base standards for social requirements.

Feature image: Green Embassy
Inset image:


Kathy Cogo is the founder and editor of Sustainable Shopper. A journalist of 15 years, she's been a senior reporter with the ABC and has managed communications and media for a range of not for profit organisations including Australia's largest organic certifying group, Australian Certified Organic.

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