Yard waste programs divert vegetative material from landfills to commercial composting or mulching facilities. These processes transform garden debris into a valuable soil amendment, which reduces methane emissions that occur when organic matter decomposes without oxygen. Because the machinery and biological processes used in large-scale composting are sensitive, the rules regarding what can be placed in a yard waste bin are often strict and vary significantly. Adhering to local guidelines is necessary to ensure the material can be successfully processed.
What Organic Materials Are Accepted
The primary purpose of the yard waste bin is to collect soft, easily compostable plant matter, which is predominantly high in carbon and nitrogen. Accepted items typically include loose leaves, common weeds, spent garden plants, and flowers, all of which break down quickly in a commercial composting system. These materials contribute the necessary “green” and “brown” ingredients that fuel the microbial activity during decomposition.
Grass clippings are also generally accepted, although some jurisdictions encourage residents to leave them on the lawn to return nutrients to the soil in a practice called “grasscycling.” When they are collected, it is usually in a paper bag or loose in the bin. Small sticks and tree trimmings are acceptable, provided they meet specific size criteria to avoid damaging the processing equipment. These woody materials must typically be no more than four inches in diameter and four feet in length.
Common Contaminants to Keep Out
Introducing materials that cannot be broken down by microbes or that physically interfere with machinery is the main reason a yard waste bin may be rejected. Physical contaminants like plastic, glass, and metal do not decompose and must be sifted out of the finished compost. This includes plastic plant pots, garden hoses, produce stickers, and any non-compostable plastic bags.
Soil, sod, and rocks are also prohibited because they are too dense and mineral-heavy, damaging the screens and shredders at the facility. Large pieces of concrete or ceramic items, like broken pottery flowerpots, will similarly ruin composting equipment. Treated or painted lumber cannot be included because it contains chemical preservatives that contaminate the final compost product, making it unsafe for gardens.
Pet waste and animal manure are often excluded due to the potential for harboring pathogens, such as E. coli and Salmonella. These pathogens may not be fully eliminated if the commercial composting process fails to reach the required sustained high temperatures. Furthermore, herbicides used on lawns or gardens can survive the composting process and later harm sensitive plants in a recipient garden.
Preparation Rules for Collection
How accepted materials are presented for collection is governed by specific rules for weight and container type. Plastic bags are universally prohibited for yard waste, even if used to line the bin, because they contaminate the compost stream with microplastics. Residents must instead use approved rigid containers, like the municipal bin, or biodegradable paper yard waste bags.
Any brush or branches that cannot fit loosely in the bin must be bundled, typically secured with natural twine or rope, which will break down during composting. The weight of any individual bag or bundle is strictly limited, often to a maximum of 40 to 50 pounds, to ensure the safety of the collection crew. Bundles must also meet the length and diameter restrictions for woody material.