We Put our Biodegradable Fibres to the Test

What does it really mean when a brand says that the fabric they’re using is biodegradable? Is it going to fall apart in the wash? Or worse, is it greenwashing and marketing hype? We, here are our Byron Bay HQ, decided to really put our claims to the test. Over a four month period, our team at Spell put six fabrications from our Summer collection into our office compost worm farm (which by the way, is super beautiful, check it out here) to see what happened.


It turns out, the claims are correct, and all of the swatches broke down in the compost, with the exception of our swimwear fabrication (a synthetic fabric made from recycled polyamide and elastane, that gives new life to pre- and post-consumer nylon waste like carpet and abandoned fishing nets).


What does this mean for your clothes? It doesn’t mean they are going to fall apart or that the fabrics are not hearty, but what it does mean is that in the right conditions (like in a compost where microorganisms are flourishing and the ratios of nitrogen and carbon are in balance) the fibres will break down and return to the land, rather than slowly decaying in landfill once it has reached the end of its life cycle.


Our Sustainability Specialist, Angie Menghini, said that whilst we primarily use plant based and certified fibres that are known to be biodegradable, it was really great for the Spell team to see these biodegradability claims in action.

“We always ensure the facts we share have documented evidence and have our annual Impact Report fully audited by an external auditor each year to verify all of our claims. Unfortunately there is little to no regulation at the moment on what brands can claim, which can make it hard for consumers to know what to believe!” Angie said. “Terms like ‘natural’ and ‘biodegradable’ have become such buzzwords as brands try to communicate their sustainability efforts and materials used, so for our team, this was an amazingly involved experiment to see first-hand that these fibres break down. We aren’t claiming perfection, and sustainability practices are continuously evolving and our learning is on-going, however transparency and accurate communication to our customers is really important to us.”


According to a report by the Australian Fashion Council, Australians are currently sending 260,000 tonnes of their wardrobes to the landfill each year. That’s equal to about 10kg of clothing per person every year.

Check out Spell’s observations over the 15 week experiment:


Week 1: We chose six of our fabrications from our Summer 2022 collection to be a part of our fibre composting experiment:

- 100% linen (woven, digitally printed)

- 45% LENZING™ ECOVERO™ viscose 55% viscose (woven, screen printed)

- 100% LENZING™ ECOVERO™ viscose (woven, digitally printed)

- 50% organic cotton 50% LENZING™ ECOVERO™ viscose (woven, digitally printed)

- 100% organic cotton poplin (woven, digitally printed)

- 85% recycled polyamide 15% elastane (machine knit, digitally printed)


We chose these fabrications because they are some of our most frequently used, and would also provide us results for a variety of weights and fibre sources.


After cutting each swatch to the same size, we secured a waterproof label to the fabric with a cable loop before tethering them to the side of the compost and burying them into the humus.


We use our office compost to dispose of our HQ team’s food scraps each day and balance the nitrogen with carbon by adding shredded paper from printed documents that are no longer needed. One to two times a week, we stir the compost in order to mix and aerate. There is also an abundant worm population that helps to break down the food, aerate the soil and keep unwanted bacteria populations in check.


At the end of each week, we dug up our fabric swatches, snapped photos and noted the changes.

Week 2 & 3: Over the first couple of weeks there weren’t any significant changes but did notice the edges of the 50% organic cotton 50% LENZING™ ECOVERO™ viscose starting to fray and split.

Week 4: This week we started to see changes that got us pretty excited to see how the whole experiment was going to play out. Each of the fabrications had become thoroughly damp due to the extended time spent in the compost. The 100% linen started to develop some splits around the edges. The 45% LENZING™ ECOVERO™ viscose 55% viscose, being a lightweight, delicate fabric of finely woven fibres, started to break down, splitting in multiple places. The 50% organic cotton 50% LENZING™ ECOVERO™ viscose started to fray and get stringy around the edges. Aside from being a bit dirty, there were no changes to the 85% recycled polyamide 15% elastane (as we would expect, as these fibres are synthetic–a plastic based fibre)

Week 5-8: By the end of week 6 we were seeing some substantial decomposition:

- Approximately 75% of the 45% LENZING™ ECOVERO™ viscose 55% viscose blend had degraded

- 10-15% of the 100% LENZING™ ECOVERO™ viscose had degraded, and more fraying around the edges

- Nearly half of the 50% organic cotton 50% LENZING™ ECOVERO™ viscose blend had degraded

- The linen and organic cotton poplin were seeing more fraying around the edges and some large splits developing in the weave

- The 85% recycled polyamide 15% elastane saw little change.

Week 9-12: We could feel the fibres had grown soft and fragile from the previous two months in the moist compost environment. You could tear each of the fabrics with your fingers, again with the exception of the swim fabric. The end of week 9 we were seeing:

- 90% of the 45% LENZING™ ECOVERO™ viscose 55% viscose blend had degraded

- Approximately half of the 100% LENZING™ ECOVERO™ viscose had degraded

- Around three quarters of the 50% organic cotton 50% LENZING™ ECOVERO™ viscose blend had degraded, the remaining fabric had faded and become string-y

- The organic cotton poplin is splitting and growing more delicate, approximately a quarter of the fabric swatch
had degraded.

- The linen, a much thicker and more robust fibre, continued to fray and become more sheer and delicate as
it degrades.

Week 13: By the end of week 13, the entirety of the 45% LENZING™ ECOVERO™ viscose 55% viscose blend and the 100% LENZING™ ECOVERO™ viscose had degraded. A small tangle of fibres from the 50% organic cotton 50% LENZING™ ECOVERO™ viscose blend remained. The linen and organic cotton poplin were thoroughly battered and degrading, with only a minority of each remaining.


Week 15: The final check at the end of week 15–All that remains is a couple small scraps of linen and organic cotton poplin the size of your finger! They will be gone by the end of week 16! Visibly, 85% recycled polyamide 15% elastane still has not changed much, but the fabric quality, stretch and rebound has deteriorated (think of your salty old bikinis in the back of the drawer you pull out and stretch to put on but they crackle and don’t bounce back).


The viscose and viscose/cotton blends were very fine gauge fibres and lightweight fabrics, we believe these were contributing factors that helped these fibres degrade faster. Linen is thicker than cotton and known to be one of the more durable and strong fibres in textiles and so it was no surprise that it took longer to biodegrade than the finer fibres. Each of these fabrics were printed either digitally or screen printed, so whilst we didn’t conduct any formal soil tests that may indicate how these colourants degraded with the fibres, we were so pleased to see that our natural fibres did truly break down in a compost setting.


Even in a flourishing compost worm garden the synthetic fibres remained intact. No surprise, but a valuable and visual dose of reality of the lingering nature of plastic based fibres.


Our whole team was excited and intrigued by this experiment, everyone found connection for different reasons–some found this valuable for communicating to our customers, but others found it interesting for their own personal purchasing knowledge.