For many people looking to minimize landfill waste, the paper plate seems like a natural addition to the compost pile. Whether you can compost them is not a simple yes or no, but rather a conditional one based entirely on the plate’s construction. Composting paper plates is possible only if they are made from certain materials and prepared correctly. Understanding the specific composition of the plate is the determining factor in a successful composting effort.
The Critical Distinction: Coated Versus Uncoated Plates
The primary obstacle to composting a paper plate is the material used for moisture resistance and integrity. Standard, uncoated paper plates made purely from wood pulp are generally compostable because they consist of organic carbon material. These plates easily break down into organic matter when exposed to microbial activity in a compost environment.
Conversely, many common disposable plates are lined with non-compostable barriers to prevent leaks. Plates coated with polyethylene (PE) or other plastic linings will not decompose and must be excluded from the compost bin, as these materials contaminate the finished product. Wax-coated plates present a similar challenge, though some modern versions may use compostable, plant-based waxes.
For a plate to be reliably compostable, it must be certified by an independent body, often indicated by seals like the Biodegradable Products Institute (BPI) certification. Many certified compostable plates, such as those made from sugarcane bagasse or paper with a polylactic acid (PLA) coating, are engineered for specific decomposition conditions. PLA, a plant-derived polymer, requires the sustained high heat and controlled environment of an industrial composting facility to break down, often taking 90 to 180 days.
Home composting systems, which operate at lower and more variable temperatures, may not break down these certified materials effectively. Items requiring industrial processing may remain intact for years in a backyard pile. Consumers must check if the plate is certified for home composting specifically. The material composition determines the plate’s final destination, whether it is the compost bin, a commercial facility, or the trash.
Preparing Compostable Paper Plates for the Bin
Once a plate has been identified as compostable, proper preparation significantly accelerates its transformation into soil amendment. Paper plates function as a “brown” material, supplying the carbon necessary to balance the nitrogen-rich “green” materials like food scraps and grass clippings. This carbon source is beneficial for microbial health and helps absorb excess moisture, preventing the pile from becoming anaerobic and producing foul odors.
The physical size of the plate is a major consideration for the decomposition rate. Adding an entire plate to the bin can slow the process considerably because the surface area available for microbial action is limited. To increase this surface area, plates should be torn into small pieces or shredded before being introduced to the pile.
The ideal size is a few square inches or smaller, which allows microorganisms to colonize the material more rapidly. These prepared pieces should be layered or mixed throughout the existing compost pile rather than being placed in a large, single clump. Incorporating the paper pieces deep within the active composting matter ensures they are subjected to the highest heat and most intense microbial activity, leading to a faster and more complete breakdown.
Managing Common Contaminants: Inks, Dyes, and Grease
Even plates made from compostable materials can present challenges due to common residues and decorative elements. The inks and dyes used to print designs on paper plates, especially bright colors, can contain unwanted substances. Some conventional printing inks may contain heavy metals (such as lead, cadmium, or chromium) or synthetic chemicals like primary aromatic amines.
These components do not break down during composting and can introduce contaminants into the finished soil. To avoid this risk, it is best to compost only unprinted or plain brown paper plates, or to tear away and discard any heavily inked portions.
Grease and oil represent another significant contaminant, though their impact depends on the quantity. A small amount of residual grease from a sandwich or a few crumbs of food will break down easily within an active, hot compost pile. However, plates heavily saturated with cooking oil or large quantities of meat fat should be avoided.
Excessive amounts of grease slow the decomposition process by creating a water-resistant barrier that inhibits microbial access to the paper fibers. Heavy grease also carries a risk of attracting pests, such as rodents, to the compost pile. To mitigate this risk, any moderately greasy plates added should be buried deep within the center of the pile. The entire bin should be turned regularly to maintain heat and proper aeration.