The Difference between Plastic, Degradable & Compostable Bags :101

Looking down the bin liner aisle of your supermarket, there is a lot of choice, from plastic to degradable and compostable. Do you know the difference? Do you know what the environmental impact of each one is?

Honestly, until very recently, I really didn’t understand the difference, so this one is for all of you out there, that is scratching their head when looking at these products and wanting to make an environmentally conscious choice. – Welcome back to “Less Waste Wednesdays“, where I will keep you updated with the positive changes my family is making on our journey to a zero-waste household. x

Every journey starts with the first step, but sometimes, that journey comes to a fork in the road – you take the left, finding yourself stumbling over a rocky outcrop, on a narrow slippery pathway, heading toward a river filled with hungry crocoldiles… in the dark. (woah, that got outta control kinda fast).

My point is, a journey that starts with a touch of education and foresight will hopefully guide you onto the path of least resistance and less likely to descend into an end where you get eaten by a crocodile.

My family and I are still in the early stages of our zero- waste journey, we still produce waste that has nowhere to go, but into our waste bin (meaning, we can’t use it again in our home, compost it in the garden, or recycle it in our yellow lid recycle bin).

Those items go into a lined bin under our kitchen sink.  I buy liners for this bin, so we have less mess inside and it’s an easy transfer from the kitchen to our waste collection bin outside.

One of the latest liners I’ve purchased was from a large chain supermarket. This product was a roll of ‘Degradable Plastic Bags’. They were packaged in a brown paper label and sported some “Green” themed images and catch phrases on the package. I’ll admit, I felt really good about myself as I purchased the roll that day, and promptly took them home to implement as part of our our zero-waste journey.

It wasn’t until that evening, after the kids had gone to bed and I was catching up on some emails that I did a little googling.  At that point all the good feels vanished, as I realised that the ‘degradable green’ bags I had purchased, are deemed no better than traditional non-biodegradable plastic bags. In fact, some sites argued they are worse as they shred down to microplastics faster than their traditional plastic counterparts… FAIL.

So, let’s talk about the difference between three basic types of plastic that we see in everyday plastic bin bags, so you can identify them in the future.


Obviously, this is the villain in our story, and that’s for good reason. Dependent on the type of Plastic we use and the thickness, it can take anywhere form decades to centuries to break down. As an added bonus, they don’t break down at a molecular or polymer level and thus create ‘microplastics’.


(including “OXO Degradable products and the “Green” friendly packaged ones I purchased recently)

This clever little product is a conventional plastic mixed with an additive to imitate biodegradation. Meaning they break down faster than traditional plastics (see above), however they still break down to microplastics, and end up in our environment for an excrutiatingly long time (we’re talking generations and generations here).


This is the one you want to go for.  This product leaves no microplastics, and can be placed in compost or organics recycling bin.

Basically they are made of substances that will allow the product to biodegrade at a certified rate in an industrial composting facility environment.  In Australia, certified “Compostable” products are labelled with this symbol.

Australian Standard for Compostability Logo
This logo is placed on products that adhere to the Australian Standard for Compostability.

So check out the products you purchase and see if they carry this symbol.

I’m intending to write a blog post around this symbol in the near future. Our certification in Australia sounds like it’s a pretty good thing and I really want to explore this further for us.


So, in summary, the best thing you can be doing is looking for “COMPOSTABLE” products. These items will break down in a composting environment.

I’ve also found this neat little graphic below to explain the above as simply as possible.

Info graphic explaining the difference between degradable and compostable plastics.
This info graphic breaks it down simply for you, the difference between degradable and compostable plastics.

In research for this post I’ve found some really interesting articles that get more into the science of this (if that’s your thing).  This site in particular did a great job explaining to me the difference between Biodegradable vs. compostable vs. oxo-degradable plastics, cause lordy knows, it’s as confusing as a break dancer directing traffic.

The lead image to this blog post came from this site, they also have some easy to follow info for you to read up about on this topic.


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