Compostable bags in landfill: why compost is where they belong

Compostable bags are designed for compost. That sounds obvious, but it's the most useful thing to know about them. Landfill is not compost, so if you want a compostable bag to do what it was made to do, put it in compost.

The good news: if your bag is certified home compostable, you don't need anyone's permission. Your own compost will do.

Why landfill isn't compost

Compost works because microbes break down organic material, and those microbes need oxygen, moisture and warmth. A well-run compost gives them all three.

Landfill is designed to do the opposite. Waste is compacted and covered to contain it, so there's very little oxygen. Food scraps, paper and compostable bags all behave differently under those conditions than they do in compost. That's why organic material in landfill is a concern in its own right, and why many councils now run FOGO collections to keep food scraps out of landfill.

So the question isn't whether a compostable bag is "better" in landfill. It's how to keep it out of landfill in the first place.

Compost it: your options

1. Home compost

ZERO's Compostable Produce Bags and Resealable Food Storage Bags are certified home compostable (TÜV Austria OK compost HOME). That means they've been tested to break down in the cooler conditions of a home compost system. Tear them into smaller pieces, mix them in with your scraps, and keep the compost damp and turned.

2. Your council's FOGO bin

If your council runs a food organics and garden organics (FOGO) service, check its rules on bags and liners. Some councils accept certified compostable bags, some supply their own liners, and some ask for no bags at all. Our guide to compostable bags and the green bin explains how to check.

3. A friend, neighbour or community garden

No compost at home? Plenty of community gardens and neighbours with compost bins welcome food scraps. Ask what they accept before you drop off bags.

Check the certification

Not every bag labelled "compostable" is made for the same kind of compost. Look for a named certification:

• AS 5810 or OK compost HOME: home compostable.
• AS 4736: commercial (industrial) compostable.

"Biodegradable" on its own isn't a compostability standard. Our guides to home compostable vs industrial and spotting greenwashing go into more detail.

What about bags that have to go to landfill?

Some waste does end up in the general bin. Most councils don't accept nappies or dog poo in the FOGO bin, for example, and not everyone can home compost pet waste safely. In those cases, follow your council's guidance.

Even then, choosing a certified home compostable bag means you're not adding conventional plastic film to the pile. And for dog poo, it keeps the option open to compost it separately wherever your setup and council guidance allow. Our guide to disposing of dog poo without plastic covers pet waste in more detail.

Why compostables are worth it

Conventional plastic film persists for a very long time. A certified compostable bag, put in the compost it was designed for, breaks down fully into carbon dioxide, water and biomass. That's the difference, and it's why the bin you choose matters.

The bags in your kitchen are a pretty easy place to start.

Setting up a simple home compost

If you don't compost yet, it's easier than it sounds.

1. Pick a system. A compost bin, a tumbler or a simple heap in a corner of the yard all work. Short on space? Check with your council, as some offer compost bins or workshops.
2. Balance greens and browns. "Greens" are food scraps and fresh garden clippings. "Browns" are dry leaves, shredded paper and cardboard. Aim for a mix of both.
3. Keep it damp. Like a wrung-out sponge.
4. Turn it. Every week or two, to keep air moving.
5. Add your bags. Tear certified home compostable bags into smaller pieces and mix them in with the rest.

Our guide to how long compostable bags take to break down has more on helping bags along.

Why not just recycle them?

Compostable bags aren't designed to be recycled with conventional plastics, and they can cause problems in that stream. Keep them out of the recycling bin and out of supermarket soft plastic collections. Compost is their home.

FAQ

Do compostable bags break down in landfill?

Landfill isn't designed for composting, and compostable bags are designed for compost. Put them in your home compost, or in your council's FOGO bin if its rules allow bags.

Are ZERO's bags home compostable?

Yes. ZERO's produce bags, resealable bags, nappy waste bags and puppy waste bags are certified home compostable.

Should I put compostable bags in the recycling bin?

No. Compostable bags aren't recyclable with conventional plastics. Put them in the compost.