Dark green background with "Compostables: Yes or no?" on the right hand side and picture of black compostable bags on the left with the words "I am not plastic" printed in the centre

Compostable Bags: How Environmentally Friendly Are They?


Compostable packaging has emerged as a worthy contender of plastic packaging, claiming to be environmentally friendly by reducing waste, and minimising environmental harm from plastic pollution. But are they truly environmentally friendly? How do they break down? Where do you send compostable packaging? Let’s go through the stats together.

What are compostable bags made of?

Compostable bags are typically made from organic materials like corn starch or sugar cane, with compostable plastics like PLA. This way, the organic materials can be eaten and broken down by microorganisms, and turned into usable, non-toxic compost.

How does this differ from biodegradable bags?

Compostable bags and biodegradable bags both refer to bags that break down, but as to HOW they break down is the key difference. The key difference being that compostable bags break down within a specified time limit, with no toxicity left behind. Whereas biodegradable bags do not have a specified time limit, and could leave toxic materials in its wake. Both the terms compostable and biodegradable refer to breaking down, but as to HOW and how LONG they break down is their key difference – with compostable being the more environmentally friendly and less harmful option.

How do compostable bags break down?

Compostable bags are designed to decompose naturally under the right conditions. When you place it into a composting environment with moisture, oxygen, and microbial activity, the bags will undergo degradation. Microorganisms will feed on the bag, and break down its molecular structure. As the temperature rises within the compost and the bag fragments into smaller pieces, it will eventually transform into nutrient rich compost. This is great for garden soil and promoting plant growth.

What happens if a compostable bag is thrown into a regular bin?

When a compostable bag is thrown into a regular bin and ends up in a landfill, its ability to break down is greatly hindered due to a few factors. Firstly, lack of oxygen. Compostable materials require oxygen to decompose properly through microbial activity. Without it, the decomposition process is slowed down and the bag may not break down as quickly or completely. The second factor is low moisture. Landfills are often compact and covered in soil. Compostable materials need moisture to facilitate microbial activity once again, and without it the bag may remain intact for a longer period of time. Lastly, methane production is a big problem. In anaerobic environments (like landfills), organic materials will decompose and product methane – a potent greenhouse gas. While compostable materials will still break down without oxygen, the process will produce methane instead of carbon dioxide that can be stored – and will contribute to climate change.

Overall, when a compostable bag ends up in the regular bin and therefore a landfill, it could take significantly longer for it to decompose compared to a proper compost environment.

So, where do we dispose of compostable bags? Industrial versus home

Annoyingly enough, disposing of compostable products is entirely locational. Some areas of the word, (like the United States, for example), do not have the infrastructure for home composting – only industrial. Therefore, if you’re going to choose compostable bags for your products it’s important to know where your customers are located and if they have access to the proper disposal methods. Luckily here in the UK, home composting and industrial composting is widely practiced. Therefore, compostable bags may be the ideal solution for UK based consumers. But, knowing whether your compostable bag is home compostable or industrially compostable is extremely important.

Industrially compostable means that your compostable bag can ONLY be properly broken down in an industrial facility meant for composting. These tend to be located in every major city in the UK and practiced widely nationally. But this means that your compostable bag CANNOT go into your home composting bin.

Home compostable means that your compostable bag can go in EITHER home or industrial compost. It is able to have its conditions for composting met easier than industrial only compost, and therefore will break down in either or – controlled or uncontrolled conditions. 

Telling the difference between these two is extremely important to ensure proper decomposition, and there are many certifications to ensure that these conditions are met. Here at SR Mailing, we are proud to say that our compostable mailing bags are home compostable and industrially compostable. Let’s cover some of these popular certifications and what they mean.

TÜV AUSTRIA: Home compostable

TUV Austria is an internationally recognised inspection body that ensures our products were examined and verified through test samples of our products, and is able to bear the OK COMPOST HOME mark. In order to be certified, our product had to break down into non-toxic material in a home compost within a time frame of around 6-12 months. The green HOME COMPOST sticker with the TUV Austria logo on it is important to look out for on compostable products so you can be sure of proper disposal, making sure it says HOME and not INDUSTRIAL ONLY before putting it in your home compost bin!

TUV Austria certification proof, with tuv austria symbol for home compostables at the top, and details of the certification at the bottom

AS5810: Australian Standard for Biodegradability

Another widely accepted compost certification, ensuring conformity with the Australian Standard for home composting! This certificate also guarantees that our mailing bags will break down into non-toxic material within a timeframe of 6-12 months. The material should disintegrate into fragments, with no more than 10% of the original mass remaining as residue visible to the naked eye after 12 weeks. The material must not contain any substances known to be harmful to human health or the environment, and should support microbial activity with a suitable substrate for microorganisms. By meeting this requirements, our compostable mailing bags demonstrate their ability for home composting once again!

Australian standard as5810 certification proof with green recycle symbol in the middle and details of certification at the bottom

EN13432: European Standard for Compostable Materials

EN13432 usually covers industrial composting as opposed to home composting, and this involves putting our product into a controlled composting commercial facility. However, our products were certified under EN13432 for compostable materials, ensuring that all the materials found in our compostable bags will break down properly in a composting environment.

DIN Certco at the top left corner, details of the EN13432 certification in the center

Are compostable bags worth it?

As we look for more sustainable solutions, it is hard to say if compostable bags are completely “worth” it. It is entirely situational. In a country where composting is the norm, they are a great option if they are getting disposed of correctly. On the other hand, in places where composting rate is rather low, it probably would not be best to use compostable bags – recycled paper or plastic will do just fine! But doing something is better than doing nothing. That is why, we can conclude that compostables have the potential to be a great solution! *Depending on your situation*! In the meantime, it is important to stay informed as new sustainable solutions (like compostable) are formed, and making sure you can make the best (and most sustainable) solution for your business. If you feel compostable mailing bags may be a good option for your business, check our bags out! If compostable bags are not right for you, check out our recycled paper or recycled plastic bags instead!


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Kun Feng
Kun Feng is the foremost sustainable packaging expert who possesses the fundamental eco-knowledge and passion necessary to drive new levels of eCommerce growth without compromising people, the planet, or the economy. 

As the co-founder and managing director of SR Mailing, He has successfully helped over 9,000 eCommerce businesses transform into sustainable suppliers and takes pride in being able to offer eco-friendly packaging solutions that bolster eCommerce reputation and scalability, all while supporting the bigger picture along the way.

Feel free to contact with Kun on Linkedin or Facebook
Kun Feng

Managing Director