Can I Compost Cardboard and Paper?

Cardboard and paper are among the most useful composting materials available — not despite being "waste", but precisely because they provide what most garden compost heaps lack: dry, carbon-rich "brown" material to balance the nitrogen-rich "greens" from kitchen scraps and grass clippings. Without adequate browns, a compost heap becomes wet, slimy, and smelly. Cardboard and paper are free, abundant, and genuinely improve compost quality when used correctly.

Which types of cardboard and paper to use

Corrugated cardboard, brown packaging card, cardboard egg boxes, toilet roll and kitchen roll tubes, cereal boxes (with glossy coatings removed), and newspaper are all excellent composting materials. Shredded office paper and envelopes (without plastic windows) can be added in moderate quantities. Avoid heavily laminated or plastic-coated packaging, foil-lined packaging (such as some takeaway containers), and paper with metallic inks in large quantities — these do not compost readily and may leave residues in the finished compost.

How to prepare cardboard for composting

Remove any tape, labels, or staples from cardboard before composting — these do not break down and will contaminate the finished compost. Tear or cut the cardboard into pieces no larger than A4 size, and ideally smaller. Soak or dampen the pieces before adding them — dry cardboard repels water initially and can form impermeable layers in the heap. Corrugated cardboard can be flattened or torn to expose the inner fluting, which decomposes faster than the solid outer layers.

Using cardboard as a heap base or weed barrier

Beyond adding it in layers to the compost heap, cardboard has several direct garden uses that simultaneously result in its composting. Laying sheets of cardboard directly on the soil surface — covered with a mulch of compost or wood chips — suppresses weeds and slowly decomposes into the soil over one to two seasons. This "sheet mulching" or "lasagne gardening" approach is an excellent way to prepare new beds on top of grass or weedy ground without digging.