Composting is a biological process where microorganisms break down organic materials, recycling kitchen and yard waste into a nutrient-rich soil amendment called humus. Newsprint is generally a welcome addition to a compost pile when handled correctly. Its structure and composition offer distinct advantages for maintaining a healthy decomposition environment.
The Role of Newspaper in Composting
Newspaper serves a significant function in composting as a source of “brown” material, providing the carbon necessary to fuel microbial decomposition. These carbon-rich materials are the energy source for the bacteria and fungi that break down organic matter. Without adequate carbon, decomposition slows dramatically, and nitrogen can be lost to the atmosphere as ammonia gas.
For optimal microbial activity, a compost pile requires a carbon-to-nitrogen (C:N) ratio ideally between 25:1 and 30:1. Newspaper is highly carbonaceous, with a C:N ratio estimated around 175:1. Therefore, it must be balanced with nitrogen-rich “green” materials like fresh grass clippings or food scraps.
Newspaper’s fibrous structure helps create and maintain air pockets throughout the compost mass. These air spaces ensure adequate oxygen circulation, necessary for aerobic decomposition. A well-aerated pile prevents anaerobic conditions that produce foul odors and slow the breakdown of materials.
Preparation and Application Techniques
Successfully integrating newsprint requires specific physical preparation to maximize its surface area. Tearing or shredding the paper into small strips, generally no wider than one inch, is recommended. This prevents the sheets from matting together into thick layers that block airflow and moisture penetration.
Before adding the shredded paper, lightly moistening it, similar to a wrung-out sponge, helps kickstart the breakdown process. Dry newsprint can repel water if applied in large quantities, which would dehydrate the surrounding materials. Introducing the paper in thin layers, alternating it with nitrogen-rich green materials, ensures a balanced mix and helps achieve the ideal C:N ratio.
A common technique involves using a ratio of roughly two parts brown material, like shredded newspaper, to one part green material by volume. This layering promotes even distribution of carbon, nitrogen, and moisture. Regular turning of the pile after adding new materials further integrates the newspaper and distributes the microorganisms.
Safety Concerns Regarding Ink and Paper Types
Concerns about composting newspaper center on the composition of the printing inks and the paper itself. Today, black and white print on standard newsprint is considered safe because most publishers utilize non-toxic soy- or vegetable-based inks. These modern inks break down readily, leaving no harmful residues in the final soil amendment.
Older newspaper print, however, may have used petroleum-based inks that contained heavy metals like cadmium or lead. While modern standards have largely eliminated these older inks, caution is advised for materials of unknown origin. The plain, non-glossy newsprint is the preferred material for composting.
Certain paper materials must be excluded entirely from the compost pile due to their additives. Glossy inserts, colored advertisements, and slick magazine pages frequently contain clay coatings, polymers, or synthetic dyes that do not decompose efficiently. Heavily dyed papers, stickers, or thick cardboard with waxy coatings should also be avoided as they may introduce undesirable chemicals or plastics.