Most paper breaks down in compost, but not all of it should go in
Plain paper — newspaper, cardboard, paper bags, shredded office paper — will decompose in a compost pile. Paper is made from plant fiber, so microorganisms and fungi can break it down over time. The catch is that not every paper product belongs in your bin. Some papers have coatings, inks, or treatments that either slow decomposition or leave residue you don't want in finished compost.
The rule is straightforward: uncoated, unbleached, or lightly printed paper is safe. Glossy paper, plastic-lined cardboard, and heavily inked materials should stay out. If you're unsure whether a specific paper will work, the safest move is to leave it out rather than risk contaminating your pile.
Key Takeaways
- Newspaper, plain cardboard, and kraft paper bags break down in compost and help balance carbon-rich materials with nitrogen-rich food scraps.
- Glossy paper, coated cardboard, and paper with heavy ink or color printing should not go in your compost bin.
- Shredding paper before adding it speeds decomposition because it increases surface area for microorganisms to work on.
- Paper alone decomposes slowly — mix it with food scraps, grass clippings, or other nitrogen sources to keep the pile active.
Paper that works in compost
Newspaper is one of the most compost-friendly papers. The ink used in most newspapers is soy-based or mineral-based and breaks down without leaving harmful residue. Shred it or tear it into strips before adding it to your pile — whole sheets mat down and block air flow. A layer of shredded newspaper between food scraps also helps control odor and moisture.
Cardboard (the plain brown kind without plastic tape or glossy coating) decomposes well. Flatten boxes and tear them into pieces roughly 2 to 3 inches across. Corrugated cardboard has air pockets that help your pile breathe while it breaks down. Remove all tape, labels, and plastic before adding it. If the cardboard was used to ship food, make sure no styrofoam packing peanuts or plastic wrap are stuck inside.
Paper bags — grocery bags, kraft paper lunch bags, and paper sacks — work fine as long as they're uncoated. Tear them into pieces and add them to your pile. Paper bags from bakeries or delis that had grease or food residue on them are still safe; the food will compost along with the bag.
Office paper and printer paper break down, though they take longer than newspaper because they're often bleached and more densely packed. Shred it first. Avoid paper with heavy ink coverage or color printing — the more ink, the slower the decomposition.
Paper that should not go in compost
Glossy paper — magazines, catalogs, and photo paper — has a plastic or wax coating that resists decomposition. This coating can persist in your finished compost and isn't something you want in soil for vegetables or ornamental plants. Leave glossy paper out entirely.
Plastic-lined cardboard is common in beverage boxes, frozen food packaging, and some takeout containers. The plastic layer won't break down in a home compost pile. Check the inside of the cardboard — if it feels waxy or plastic-like, don't compost it. The same goes for cardboard with plastic windows or plastic tape still attached.
Paper with heavy ink or color printing — like colored junk mail, printed advertisements, or glossy flyers — should be avoided. The inks and dyes can contain heavy metals or chemicals that persist through decomposition. Plain black-and-white newspaper is fine; colored printing is not.
Paper products with food coatings like pizza boxes (which have grease and sometimes plastic coating), wax-lined paper cups, and laminated food packaging don't belong in compost. The coatings prevent decomposition and can contaminate your finished product.
How to prepare paper for your compost pile
Shredding or tearing paper before adding it to your pile makes a real difference. Whole sheets of newspaper or cardboard mat down, trap moisture, and create dense layers that block oxygen. Shredded paper has much more surface area, so microorganisms can work on it faster. Aim for pieces roughly 1 to 3 inches across.
Wet the paper slightly before adding it if your pile is dry. Paper alone decomposes slowly because it's carbon-rich and lacks the nitrogen that speeds decomposition. Mix shredded paper with food scraps, grass clippings, plant trimmings, or other green materials. A rough ratio is 3 parts paper to 1 part food scraps or fresh plant material. If your pile smells sour or soggy, you've added too much paper or not enough air — turn the pile and add more coarse material like twigs or straw.
Why paper matters in compost
Paper is valuable in compost because it provides carbon, which microorganisms need to balance the nitrogen in food scraps and grass clippings. Without enough carbon material, a pile becomes too wet, smells bad, and attracts pests. Paper helps regulate moisture and keeps the pile aerobic (oxygen-rich), which speeds decomposition and reduces odor.
The trade-off is that paper alone won't heat up or break down quickly. A pile made only of paper will sit for months or years without much change. That's why mixing paper with food scraps and other nitrogen-rich materials is the key to a working compost system.
Paper from treated or recycled sources
Recycled paper is fine to compost as long as it's not glossy or heavily printed. The recycling process removes most contaminants, and the paper will break down like any other uncoated paper.
Paper that has been treated with chemicals — like paper used to line animal bedding, paper with fire-retardant coating, or paper from industrial processes — should not go in compost. If you're not sure whether a paper product has been treated, leave it out. The risk of introducing unwanted chemicals into your soil isn't worth the small amount of carbon you'd gain.
Frequently Asked Questions
Can I compost paper with ink on it?
Black-and-white newspaper ink is safe to compost. Most modern newspaper inks are soy-based or mineral-based and break down without leaving residue. Colored printing and glossy magazine ink should be avoided because they may contain heavy metals or dyes that persist in finished compost.
How long does paper take to decompose in compost?
Shredded newspaper typically breaks down in two to six months, depending on pile temperature and moisture. Cardboard takes longer — six months to a year — because it's thicker and denser. Paper alone decomposes much more slowly; mixing it with food scraps and green materials speeds the process significantly.
Will paper make my compost pile smell bad?
Paper itself doesn't cause odor. Bad smells come from too much moisture and not enough air, which can happen if you add too much paper without mixing it with coarser materials or if you don't turn the pile. Shred paper, mix it with food scraps and grass clippings, and turn the pile every week or two to keep it aerobic.
Is it okay to compost paper bags that had food in them?
Yes. Paper bags from bakeries, delis, or grocery stores are fine to compost even if they have food residue on them. The food will compost along with the bag. Just make sure the bag itself is plain kraft paper without plastic coating or wax lining.
Can I use compost with paper in it for vegetable gardens?
Yes, as long as the paper you added was uncoated and unprinted or printed only with black-and-white newspaper ink. Finished compost made from plain paper, cardboard, and food scraps is safe for vegetable gardens, flower beds, and houseplants. If you added glossy or heavily printed paper, don't use that compost for food crops.