Compostable vs Plastic Dog Poo Bags: Why the Switch Actually Matters
If you walk a dog once a day, you will get through somewhere around 365 poo bags a year. Multiply that by 11.1 million dogs in the UK, and the type of bag we all reach for stops being a small choice.
If you walk a dog once a day, you will get through somewhere around 365 poo bags a year. Multiply that by 11.1 million dogs in the UK, and the type of bag we all reach for stops being a small choice.
What a standard plastic bag actually is
Most cheap poo bags are made from conventional plastic, usually polyethylene, the same base material as a bin liner or a supermarket carrier bag. It is strong, cheap and does the job in the moment. The problem is what happens after it goes in the bin: it can take hundreds of years to break down, and even then it does not disappear, it fragments into microplastics that persist in soil and waterways indefinitely.
"Biodegradable" is not the same as "compostable"
This is where a lot of well meaning dog owners get caught out. A bag labelled biodegradable simply means it will eventually break down, but there is no guarantee of how long that takes or what it breaks down into. Many biodegradable plastic bags still rely on petroleum based plastic with additives designed to help it fragment faster, which can mean it breaks into smaller plastic pieces rather than disappearing entirely.
Compostable is a stricter, certifiable standard. A genuinely compostable bag is made from plant based materials, like cornstarch, and is designed to fully break down into water, carbon dioxide and biomass, leaving nothing toxic behind. Look for certification such as EN 13432, the recognised European standard for compostability, rather than taking the word "eco" on a label at face value.
Does it actually make a difference where the bag ends up?
Being realistic, most poo bags in the UK end up in general waste, which is typically sent to landfill or incineration, not a home compost heap. Even accounting for that, compostable bags still come out ahead:
- They are made from renewable plant material rather than fossil fuels
- If they are incinerated, plant based bags generally produce less ash and fewer harmful residues than conventional plastic
- If one is ever lost outdoors, lost in the countryside, blown from a bin, or yes, left hanging on a tree, it will not persist as plastic pollution for centuries
- They support demand for genuinely biodegradable materials over "eco washed" plastic alternatives
What to actually look for when buying
- A recognised certification mark such as EN 13432 or OK Compost, not just the word "biodegradable" on its own
- Enough strength and thickness that you trust it not to tear mid pick up, a common complaint with poorly made compostable bags
- A size that actually fits your dispenser and your dog
The honest bottom line
Switching to compostable bags will not single handedly solve plastic pollution. But it removes one small, entirely avoidable source of long lasting plastic waste from your household, multiplied by every walk, every year, for the life of your dog. It is one of the easiest genuine environmental swaps most of us will ever make.
Quick FAQ
Is biodegradable the same as compostable?
No. Biodegradable simply means it will eventually break down, with no guarantee of timeframe, while compostable is a certifiable standard (look for EN 13432) for full breakdown into non-toxic components.
Do compostable bags cost much more than plastic ones?
The price gap has narrowed considerably, for most households it works out to a few pounds a month, a small cost for a genuine reduction in long term plastic waste.