What's the difference between bioplastic, biodegradable plastic, and compostable plastic?

When it comes to sustainable materials, we all know that plastic is at the bottom of the list. The problem is, it’s still often hard to avoid.

If you have to use plastic, you might consider a more “eco-friendly” option to reduce your environmental impact. Something like biodegradable plastic - or even bioplastic or compostable plastic.

But what do these terms even mean? And are they even better than your regular, everyday plastic?


Biodegradable vs bioplastic - what’s the difference?

Sometimes, it might feel like “biodegradable plastic” and “bioplastic” get used interchangeably. The truth is, there’s a big difference between them.‍

Bioplastic describes what the plastic is made from.

Biodegradable describes what happens after you use it.

While regular plastic is made from petrochemicals (i.e. fossil fuels), bioplastics are made from plant-based materials. Things like the vegetable oils from sugarcane or corn. Even though bioplastics are made from natural, renewable resources, they can still take many years to break down and can still pollute the environment.

In other words, just because something is a bioplastic, doesn’t mean it is always biodegradable.

Biodegradable plastics are plastics that can break down into their natural components. 

‍Why is this good?

Basically, it means that the material doesn’t hang around in our environment for decades causing damage to our ecosystems and wildlife.

So, if you can find a bioplastic that’s biodegradable, you get a circular system! From nature, then back to nature.

Unfortunately, there’s a few more red flags to look out for on the way.


What about degradable plastic?

Be careful with labelling! “Degradable” plastic might sound like “biodegradable”, but it’s a very different story.

These “degradable” or “oxo-degradable” plastics do break down into smaller pieces over time - just not into the tiny natural compounds that they are made from. Instead, they disintegrate into smaller particles of plastic.

In many ways, this is worse than your traditional, non-degradable plastic bag. The small plastic particles are called “microplastics”, and they can continue to cause serious damage to our natural environment, particularly our marine life. However, they are so small that they are hard to track and clean up.

The trouble is, some types of plastics are labelled as “biodegradable” but are really just “degradable” or “oxo-degradable”. There are some steps being taken to improve labelling on these, but for now you may need to do some background research on the brands you use.

So - biodegradable is better than degradable or oxo-degradable (assuming the labelling is accurate!).

What about compostable?

When should I use compostable plastic?

Compostable plastics are a type of biodegradable plastic. Again, they can break down into their natural components. The main difference is the time frame that this can happen in.

Compostable plastics normally break down in a matter of months, turning into carbon dioxide gas and food for microorganisms (compost). This compost can then be used to help fertilise soil and increase crop production or other plant growth.

This seems like the best solution so far, the only issue is that they can’t all just be thrown in your backyard compost bin. Compostable plastics are still quite hard to break down, and most of them can only be composted in special industrial facilities that use higher heats.

Look out for the labelling so you know how to dispose of them.

If you put compostable plastic in landfill, it can break down without the composting part - releasing methane and causing even more greenhouse gas emissions!

If you’re using compostable plastic that needs to be sent to an industrial composting plant, it’s important to make sure that you have access to one. Some local councils do this as part of their green waste collection, but not all of them.

What’s the final verdict?

As you can see, the best option is not always clear cut when it comes to “eco-friendly” or “bio” plastics. 

Option A is to avoid plastics altogether, or reuse what you can.

In particular, try to avoid degradable plastics, as they can cause even more problems than regular plastic by breaking down and spreading throughout the environment.

If you do want to use a biodegradable plastic instead, it’s best to look for “compostable” plastics and ensure you can dispose of them properly.

And finally, you can try to use recycled and recyclable plastics. While these don’t break down into their natural components, they do preserve resources. Find out more about these options here.

🌾 bioplastics🧴 plastics

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