Can You Compost Compostable Plastics?
Yes, with care. Most 'compostable' plastics, such as PLA cups and bags, are designed for industrial facilities and rarely break down in a backyard pile. Only items certified for home composting, such as 'OK compost HOME', suit a home bin.
At a glance
| Home compost pile | With care |
|---|---|
| Green or brown | Neither (not a green or brown input) |
| Moisture | Dry |
| Prep | Shred or tear |
| Worm bin | No |
| Bokashi | No |
How to compost compostable plastics
Check the label: 'OK compost HOME' from TÜV Austria, or a similar home-compost certification, means it's designed for backyard conditions. Cut home-compostable items into small pieces and bury them in the active center. Items marked only 'compostable', or certified to industrial standards such as BPI or ASTM D6400, need a commercial facility.
Send industrially compostable items to a municipal program only if it explicitly accepts them, since many don't; otherwise, trash them. Reusable containers avoid the question.
What goes wrong
Industrial-only items sit intact in a home pile for a year or more and break into plastic fragments. Pick them out when you sift. 'Biodegradable' on a label means very little on its own.
Worm bins and bokashi
Worm bin: Keep compostable plastics out of worm bins; even home-certified items break down too slowly there.
Bokashi: Bokashi won't break down compostable plastics.
Balancing the rest of your pile? Check the balance with the compost mix calculator.
From hopcompost.com/can-you-compost/compostable-plastics/ · General guidance, not professional advice.
Frequently asked questions
Do compostable bags break down in home compost?
Only if they're certified home-compostable. Bags certified to industrial standards usually need the sustained heat of a commercial facility.
What's the difference between biodegradable and compostable?
'Compostable' products are certified to break down under set conditions within a set time. 'Biodegradable' has no fixed timeframe and is often just a marketing term.
Is PLA compostable at home?
Generally not. PLA usually needs the sustained high temperatures of industrial composting, so it lingers in backyard piles. The same goes for many 'compostable' tea bags and coffee pods.