How to Get Rid of Compost Smell: Simple Fixes That Work

Composting, the process of converting organic waste into nutrient-rich soil (end-use compost), can be a delightful journey from waste to wonder, whether you're a backyard gardener, indoor worm composter, or even if you are sending your organic waste to a curbside compost collection process. This said, many newcomers can be worried about potential odors. Learn how and why, when done right, composting can be a smell-free, sustainable operation that mitigates your environmental impact while helping our soils.

Potential Causes of Odor During the Composting Process

Composting odors primarily come from the metabolic activities of bacteria, microorganisms, and small organisms during the decomposition process of organic materials. When these organisms break down complex compounds, they release volatile organic compounds (VOCs) and other byproducts. A well-balanced composting system ensures the efficient breakdown of materials, minimizing the production of malodorous compounds (AKA, rotten smells). However, an imbalance, often caused by factors such as inadequate aeration, excessive moisture, or improper carbon-to-nitrogen ratio, can disrupt proper microbial activity and result in the generation of unpleasant smells. These odors act as indicators, signaling that adjustments are needed in the compost pile to restore a favorable environment for effective decomposition.

Maintaining a Proper Carbon:Nitrogen (Browns:Greens) Ratio

At the heart of odor management is the balance between carbon-rich and nitrogen-rich materials. Ideally, a compost pile should have a mix of green, nitrogen-rich materials (such as grass clippings and kitchen scraps) and brown, carbon-rich materials (such as shredded newspapers, straw, and leaf litter). This balance ensures a smoother decomposition process and reduces the chance of developing odors​. We recommend maintaining a ratio of 70% browns to 30% greens.

Ensuring Hydration and Ventilation in Your Compost Bin

A compost bin should be as wet as a wrung out sponge. Maintaining moderate humidity is key to eliminating odors. At the same time, turning the compost frequently ensures that it is well ventilated, providing oxygen for the working microorganisms, and prevents the compost from becoming anaerobic and creating odors.

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About Let’s Go Compost

Let’s Go Compost is a national nonprofit making composting simple, affordable, and accessible. Our programs bring hands-on composting to communities, helping people turn food and plant waste into healthy soil that supports food systems, native plant ecosystems, and pollinators. Learn more at letsgocompost.org and support our work at letsgocompost.org/donate.