Most paper bags break down in compost, but not all of them will
Plain paper bags—the kind you get from a grocery store or bakery—will compost. Paper is made from plant fibers that microorganisms can digest, so it belongs in your compost bin or pile. The catch is that many paper bags have a plastic or wax coating, a plastic window, or ink that changes whether they actually belong there.
Before you add any paper bag to your compost, look at it closely. If it feels slick or waxy, if it has a clear plastic window, or if it's printed with colored ink, it may not fully break down. Some of these materials will sit in your finished compost for months or years without decomposing.
Key Takeaways
- Uncoated kraft paper bags with black or brown ink will compost in a standard home pile within a few months.
- Paper bags with plastic coatings, plastic windows, or colored inks should not go in compost because the plastic or ink will not break down.
- Shred or tear paper bags into smaller pieces before adding them to speed up decomposition.
- If you are unsure whether a bag has a coating, feel it or hold it up to light—coated bags feel slick or show a plastic layer.
How to tell if your paper bag is safe to compost
The easiest test is to feel the bag. Uncoated kraft paper feels dry and slightly rough. If it feels slick, waxy, or plasticky, it has a coating and should not go in compost. Hold the bag up to light—if you see a shiny layer or a plastic window, that is a sign to leave it out.
Check the ink color. Black or dark brown ink is typically soy-based or mineral-based and will compost. Bright colored inks—red, blue, green, gold—often contain synthetic dyes that do not break down in a home compost pile. If the bag is printed with a logo or text in color, compost only the plain parts.
Look at the seams and bottom. Some paper bags are glued together with plastic adhesive. If you can peel the seams apart and see plastic strips, the bag is not suitable for compost. Bags held together with paper tape or kraft adhesive are fine.
Paper bags with plastic coatings and windows
Many paper bags used for takeout, deli items, or baked goods have a thin plastic coating on the inside. This coating keeps grease from soaking through, but it also means the bag will not fully compost. The plastic layer will remain in your pile long after the paper has broken down.
Paper bags with plastic windows—common on seed packets, flour bags, or snack bags—should also stay out of compost. The window will not decompose, and you will end up picking pieces of plastic out of your finished compost or spreading it into your garden.
If you are not sure whether a bag has a coating, try tearing it. Uncoated paper tears cleanly. Coated paper resists tearing or shows a plastic layer when torn.
How to prepare paper bags for composting
Tear or shred the bag into pieces roughly the size of your hand. Smaller pieces break down faster than whole bags, which can take several months to decompose. Shredding also helps the bag mix better with other materials in your pile.
Wet the pieces lightly before adding them. Dry paper can blow away and takes longer to start decomposing. A quick spray from a hose or a dunk in water is enough.
Add shredded paper bags along with food scraps, grass clippings, or other green materials. Paper is a brown material (carbon-rich), so balance it with nitrogen-rich greens. A pile that is mostly paper will compost slowly. Aim for roughly three parts brown to one part green by volume.
What happens to paper bags in commercial compost
Commercial composting facilities operate at higher temperatures and with more aggressive mixing than home piles. Some facilities will compost paper bags with plastic coatings because the heat and processing break down materials faster. However, this depends on the facility's equipment and standards.
If you have access to commercial compost pickup or a drop-off site, check their rules before adding coated paper bags. Many facilities have a list of acceptable materials on their website or printed materials. When in doubt, ask directly—it takes one phone call to confirm.
Paper bags you should never compost
Do not compost bags that held chemicals, pesticides, fertilizers, or other toxic substances. Even if the bag itself is plain paper, residue from the contents can harm your compost and your garden.
Bags with glossy or laminated finishes should stay out. These are often used for premium packaging and have multiple plastic layers. Bags that smell strongly of plastic or chemicals are also a sign to skip composting.
Shredded paper from a paper shredder is not the same as a paper bag, but the same rule applies: if the paper came from a document printed in color or on glossy stock, compost only the plain white pages.
Alternatives if your paper bag is not compostable
Paper bags that are not suitable for compost can go in your regular recycling bin if they are clean and dry. Most curbside programs accept kraft paper bags. Bags that held food or are wet should go in the trash instead, because wet paper clogs recycling equipment.
You can also reuse paper bags for storage, as liners for trash cans, or as mulch in your garden beds. Uncoated bags break down in soil over time, adding organic matter. Coated bags last longer and can be reused several times before disposal.
Frequently Asked Questions
Can I compost a paper grocery bag with a plastic handle?
No. Remove the plastic handle and compost only the paper part. The handle will not break down and will end up in your finished compost or garden. Handles are usually glued or stapled on, so they come off easily.
What if I accidentally put a coated paper bag in my compost?
It will not harm your pile. The bag straightforward will not decompose. When your compost is finished, you may find pieces of plastic or coating mixed in. Sift them out before using the compost in your garden, or pick them out by hand.
Do paper bags compost faster if I soak them first?
Soaking speeds up the process slightly, but shredding is more effective. Wet paper begins to break down faster, but the real time-saver is making the pieces smaller. A shredded wet bag will compost in weeks; a whole dry bag can take several months.
Are brown paper lunch bags safe to compost?
Most are, but check first. Plain kraft paper lunch bags with black or brown ink compost fine. If the bag has a plastic window, colored printing, or a waxy feel, it is not suitable. When in doubt, tear a small piece and feel it or hold it to light.
Can I compost paper bags that held flour or sugar?
Yes, if they are uncoated. Flour and sugar residue will not harm your compost—they are organic materials that break down easily. Bags that held these items are usually plain kraft paper. Check for plastic windows or coatings before adding them.