In 1990, approximately 25 million tons of grass, leaves, and branches were interred in American landfills each year. By 2018, this volume had decreased to about 10.5 million tons, despite households and businesses producing slightly more yard waste compared to three decades prior, as per EPA’s yard trimmings data.
Yard trimmings represent a unique waste stream where the collection and reuse systems have largely been effective. Numerous municipal recycling programs have successfully developed side ventures selling compost and soil derived from reclaimed yard waste.
The implementation of state landfill bans, the rise of municipal composting programs, and the practice of leaving grass clippings on lawns have transformed what was once the largest organic material in trash into one of the most recycled. Currently, 63 percent of the nation’s yard waste is composted or mulched.
However, the term “mostly worked” comes with a caveat: the material that still ends up in landfills is primarily the fast-rotting grass and leaves, which generate methane at a rate faster than it can be captured by landfills.
A Quarter of the Landfill, Reclaimed
The gradual success of yard-waste collection can be easily overlooked. In 2018, the U.S. produced 35.4 million tons of yard trimmings, including grass, leaves, and tree and brush trimmings, accounting for 12.1 percent of all municipal solid waste. Of this, 22.3 million tons were composted or mulched, reflecting a 63 percent recovery rate. This is among the highest diversion rates for any major material in the waste stream, marking a significant shift from 1990, when only 4.2 million tons were composted and over 25 million tons were landfilled.
Three key factors contributed to this change. Many states have imposed restrictions or bans on landfill disposal of yard trimmings for many years—Pennsylvania since 1990, Minnesota since 1994, and West Virginia since 1997, as documented by the Institute for Local Self-Reliance. California now mandates statewide diversion of yard materials under its organics law, SB 1383, fully effective in 2022. Municipal composting and curbside collection provide residents with a disposal option for yard debris separated from household waste.
Grasscycling, which involves leaving clippings on the lawn instead of bagging them, has removed a substantial portion of the material from the waste stream before it ever reaches collection trucks.
The benefits extend beyond just freeing up landfill space. Composting restores nutrients and carbon to the soil and, since it is largely a local process—where organic material is collected and processed in the same county, city, or neighborhood—it also promotes local employment, as highlighted by the EPA’s composting overview.
The Methane Asterisk
Nonetheless, 10.5 million tons of yard trimmings still end up in landfills annually, comprising 7.2 percent of all U.S. landfill content. Their impact is greater than their weight suggests. Municipal solid waste landfills rank as the third-largest source of human-related methane emissions in the United States, contributing to about 14 percent of the national total in 2022. Organic materials such as food waste, yard trimmings, wood, and paper constitute 51.4 percent of landfill content, and their anaerobic decomposition produces methane, a greenhouse gas 28 times more potent than carbon dioxide.
The timing of yard waste decomposition poses a unique challenge. It decomposes before landfill gas-collection systems are installed and activated, often years after the organics are buried. Fast-decomposing, wet materials like summer grass clippings break down before gas capture equipment is operational, allowing much of the methane to escape.
“If there is no immediate gas capture system, it is likely that all of the fresh wet materials will have significantly decomposed before the gas collection system gets turned on,” University of Washington soil scientist Sally Brown explained in a BioCycle analysis of landfill gas environmental impacts.
Not all yard waste behaves similarly, influencing how it should be managed. Woody materials, including branches and wood chips, are high in cellulose and other slow-degrading compounds; in a dry sanitary landfill, they can remain nearly inert, effectively storing carbon rather than releasing methane. Grass and leaves serve as the primary methane generators.
What It Costs Your Household
Households that bag yard waste and leave it at the curb often incur double costs: once for hauling the material away through bag fees, sticker tags, or collection charges, and again to repurchase the same nutrients as fertilizer, mulch, and compost.
The savings from avoiding these purchases can be significant at retail prices. A 40-to-45-pound bag of compost costs between $3 and $10, bulk compost is priced at $20 to $50 per cubic yard, and mulch costs range from $15 to $65 per cubic yard before delivery, according to HomeGuide’s 2026 cost data. Households that compost their own leaves and clippings can bypass much of this expenditure.
Grasscycling completes the nutrient cycle for lawns. Clippings left on the lawn can supply up to 25 percent of a lawn’s annual fertilizer needs, containing approximately four percent nitrogen, two percent potassium, and one percent phosphorus, per the University of Missouri Extension. Mowing slightly higher to facilitate grasscycling also promotes deeper roots and reduces the need for watering.
While the direct monetary savings for most households are modest—tens rather than hundreds of dollars annually—they depend on gardening habits. The labor savings from skipping bagging, along with the long-term soil and water benefits, represent the real value. Retaining biomass in your yard means those nutrients don’t need to be replaced by synthetic fertilizers, potentially saving hundreds of dollars annually.
The Template Other Organics Haven’t Matched
The yard-waste model’s success starkly contrasts with the management of food waste. Food remains the most prevalent material in U.S. landfills and accounts for 58 percent of landfill methane emissions, yet only about five percent of wasted food is composted.
Yard trimmings serve as a proof of concept. Landfill bans, accessible collection, and the simple behavior change of leaving clippings in place successfully diverted a significant organic material from landfills to soil within a generation. The methane caveat reminds us the task isn’t complete, highlighting the importance of prioritizing the diversion of the fastest-rotting materials first.
What You Can Do
- Leave clippings on the lawn. Mow when the grass is dry and remove no more than a third of the blade so small clippings fall to the ground and break down quickly.
- Mulch leaves in place. Run a mower over fallen leaves rather than bagging them; the shredded leaves feed the soil and suppress weeds.
- Compost at home. Check out our guide to the types of composters available and how to balance your compost with carbon-rich “browns” (dry leaves, wood chips) with nitrogen-rich “greens” (grass, food scraps) at roughly a 2:1 ratio of browns to greens, and keep the pile as moist as a wrung-out sponge.
- Use curbside or drop-off collection. Where it is offered, keep yard waste source-separated and out of plastic bags so it can actually be composted.
- Buy and use local compost. Closing the loop on the nutrients cuts both fertilizer and water use.
- Push for policy where composting is needed. If your state or city still landfills yard trimmings, support landfill bans and curbside organics programs, the policies that drove the national turnaround.
- Find a local option. Look up nearby composting and yard-waste drop-off through Earth911’s recycling search.
.
