Composting is a natural process that transforms organic waste into a nutrient-rich soil amendment, resulting in finished compost. Since paper is a common household material derived from plant fibers, it can generally be included in this process. However, its suitability depends heavily on the type of paper and how it has been treated.
Paper’s Role in a Healthy Compost Mix
Paper acts as a “brown” material, providing carbon essential for microbial energy. Microorganisms require both carbon and nitrogen for protein synthesis and reproduction. Efficient composting requires a Carbon-to-Nitrogen (C:N) ratio between 25:1 and 35:1.
Because paper has a very high C:N ratio, sometimes exceeding 100:1, it helps balance nitrogen-heavy “green” materials like food scraps and grass clippings. Adding paper prevents the pile from becoming dense or waterlogged, which can lead to anaerobic decomposition and foul odors. The fibrous structure of paper, particularly corrugated cardboard, also helps create air pockets, ensuring the necessary oxygen supply for aerobic microbial activity.
Types of Paper Suitable for Composting
Many common paper products can be safely added to compost, provided they lack heavy coatings or treatments. Plain corrugated cardboard is an excellent choice, with all plastic tapes and labels removed, because its structure helps maintain aeration. Newspaper is also suitable, especially the black and white sections, as modern printing inks are typically soy- or vegetable-based and non-toxic.
Shredded office paper, especially white or pastel colors, is an effective carbon source that breaks down quickly. Other plain, uncoated products like paper towel and toilet paper rolls, unbleached coffee filters, and paper egg cartons are fully compostable. These items must be composed of clean, uncoated cellulose fibers that microbes can easily access and break down.
Paper Products to Never Add
Certain paper products must be excluded because they contain non-biodegradable materials or harmful chemicals. Glossy magazines, brochures, and colored wrapping paper often have coatings that prevent decomposition and introduce microplastics into the finished compost. Any paper with a wax or plastic lining, such as milk cartons or most disposable coffee cups, will not break down in a home composting system.
Thermal receipts must be avoided, as the paper is often coated with endocrine disruptors like Bisphenol A (BPA) or Bisphenol S (BPS). Additionally, exclude paper contaminated with non-compostable materials, such as cleaning chemicals, oil, or pet waste, to prevent the introduction of pathogens or toxins. Highly colored or “flood-coated” paper should be viewed with caution, as the pigments may contain heavy metals or other undesirable compounds.
Techniques for Adding Paper Successfully
Proper preparation of paper is necessary to ensure it integrates well and decomposes within the compost mixture. Paper and cardboard should be shredded or torn into small pieces to increase the surface area available for microbial action. Large, intact pieces can clump together, restricting airflow and slowing the entire composting process.
It is beneficial to pre-wet the paper before adding it, especially with denser materials like cardboard. This prevents dry paper from creating moisture-free pockets that inhibit microbial growth and decomposition. The prepared paper must then be layered with nitrogen-rich “green” materials to maintain the optimal C:N balance. A good practice involves alternating thin layers of wet, shredded paper with layers of food scraps or fresh yard waste for even distribution.