What does biodegradable mean – green or greenwashing?

what does biodegradable mean?
This "biodegradable" cup has spent two years in a compost bin.

We’ve all been there. Gone for a lovely walk in the woods and stumbled across the crumbling remains of a crisp packet dating back to the days when Skips only set you back 7p. But that’s OK; give it another four decades and it’ll have crumbled away to nothing – far more biodegradable than Endurance, which is still intact a century after it sank. Oh, that pesky long-lasting oak!

Putting aside such nonsense, this does raise the question, what does it mean for something to be biodegradable? If we buy something marked ‘biodegradable’ or ‘compostable’ can we tick the ‘green’ box, or do we need to think a bit harder?

What does biodegradable mean?

Collins English Dictionary defines biodegradable as ‘capable of being decomposed by bacteria or other biological means’. This is a good starting point, but it leaves lots of crucial questions – what conditions are needed for decomposition to take place, how long will it take and what will the end products be? After all, it’s no good feeling smug about reducing landfill if we are damaging the environment in other ways instead. So ideally, we would want a biodegradable material to decompose quickly (months rather than years) into non-toxic compounds such as water and carbon dioxide.

Toxic remains

Sadly, biodegradable materials sometimes break down into chemical nasties. For example, without enough oxygen, decomposing vegetation produces methane, which is a potent greenhouse gas. Another example is receipts produced by a thermal printer – these contain bisphenol A (BPA), so recycling or composting these receipts would release traces of BPA, which could have adverse health effects. And that crisp packet? It’s not breaking down into harmless materials at all, it’s just fragmenting into hundreds of tiny pieces – microplastics – that could end up polluting the environment for years to come.

Conditions matter

It gets even more complicated when we look into the conditions needed for decomposition. Some products that will decompose on your home compost heap simply won’t break down in landfill because there isn’t enough bacteria, heat, light or oxygen. Other products, including some labelled ‘compostable’, only break down in very specific conditions within industrial composting facilities -your home compost heap or standard food waste plants simply won’t do the job. There are very few composting facilities in the UK, so your compostable coffee cup is very likely to end up in landfill, which is worse for the environment than a recyclable plastic cup. The same goes for many biodegradable plastics and bioplastics – in Surrey and Hampshire these are not accepted for recycling and are simply sent to landfill. They aren’t even suitable for home composting because of the chemicals they contain. They might be biodegradable in theory but not in practice.


What next?

At this point it’s tempting to give up trying but there are still plenty of small changes we can all make that will add up to a big difference.

Firstly, don’t just assume that being marked biodegradable or compostable is a good thing, ask questions, check how it was made and where it can be dealt with, find out if it’s really the greenest option. Veer towards products that you know can easily be recycled, such as cardboard, paper and aluminium.

Secondly, check out where else you may be able to recycle products the council won’t collect. More and more shops now have collection points for tetrapaks, soft plastics, cosmetics packaging and more.

Thirdly, cut down on single use products. Take your own coffee cup out with you, use silicon or wax food wraps, swap tea bags for loose tea, check out your local refill shop or online eco shop for a full range of plastic-free products from toothbrushes to scrubbing brushes.

Biodegradable may not be the answer we thought it was but there are still plenty of ways to be a little greener.




  1. Degradable packaging sounds like a good idea. BUT that is another crop we have to farm/grow intensively to make it cost effective. Madagascar is growing cash crop such and vanilla and sisal to be made into packaging.
    To grow these cash crop unique animal and plant habitat is cut down for these farms.
    Madagascar is home to an abundance of plants and animals found nowhere else on Earth. Approximately 90 percent of all plant and animal species found in Madagascar are endemic.
    So better to have no packaging at all especially plastic which keeps the moisture accumulates inside and the food rots while in store. adding to food waste.


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