Can You Compost Cardboard?
Yes. Plain corrugated cardboard is an easy, high-carbon brown, roughly 350:1 C:N, ideal for balancing wet kitchen scraps. Remove tape and labels, tear it into small pieces, and soak it if your pile runs dry.
At a glance
| Home compost pile | Yes |
|---|---|
| Green or brown | Brown (carbon-rich) |
| Carbon to nitrogen | about 350:1 (approximate) |
| Moisture | Dry |
| Prep | Shred or tear |
| Worm bin | Yes |
| Bokashi | No |
How to compost cardboard
Strip off plastic tape and shipping labels, then tear or cut cardboard into pieces about 2–4 in (5–10 cm). Soak it in water for a few minutes if the pile is dry. Use it at about 2–3 parts browns to 1 part greens, alongside leaves if you have them.
Flattened cardboard also works as a weed-smothering layer under mulch when you start a new bed.
What goes wrong
Flat sheets mat down, block air and stay intact for months. Tear pieces smaller and mix them in rather than laying whole sheets. Waxed or plastic-coated boxes, such as some produce boxes and frozen-food cartons, don't break down; recycle or trash those.
Worm bins and bokashi
Worm bin: Shredded, damp cardboard is one of the best worm bin beddings, and worms eat it too.
Bokashi: Cardboard doesn't go in the bokashi bucket; save it for the pile, where it balances fermented scraps.
This counts as a brown. Adding a lot of it? Check the balance with the compost mix calculator.
From hopcompost.com/can-you-compost/cardboard/ · General guidance, not professional advice.
Frequently asked questions
Can you compost pizza boxes?
Yes, if they're plain cardboard. Light grease stains are fine; scrape off cheese and remove any plastic tables or liners.
Should I remove tape before composting cardboard?
Yes. Most packing tape is plastic and won't break down. Plain paper tape is fine.
Can you compost printed cardboard?
Plain brown cardboard with some printing is fine. Glossy, heavily coated boxes are better recycled, like glossy paper.