What is compost?
Did you know that compost can be used to stimulate plant growth, reduce the need for chemical fertilizers, and lower harmful greenhouse gas (GHG) emissions?
Compost is made from decayed organic materials, such as food or plant matter. The aerobic reaction (with oxygen) that occurs during composting leverages naturally occurring microorganisms to break down the organic materials, leaving behind a stable, nutrient-rich product called “humus,” aka compost, which can be sustainably repurposed back to the environment rather than sitting in a landfill.
When food decays in landfills anaerobically, GHG—such as methane—is released into the atmosphere due to lack of airflow. Composting reduces GHG because it allows food to decompose in the presence of oxygen, thereby producing more organic, reusable material.
Composting helps improve our soil by:
- Activating microbial life and supporting plant nutrition.
- Sequestering excess carbon from the atmosphere.
- Improving the soil’s water filtration and retention rate.
- Building upon existing microbial life in the soil.
How does composting work?
Organic matter will naturally decompose as part of its life cycle. When combining reactants like the ones below, composting speeds up the decomposition process by providing an ideal environment for bacteria and fungi to work together.
Four basic ingredients are needed for food scraps to decompose:
“Browns” in composting are carbon rich. Known as a key component of life, carbon provides the main nutrient source for compost microbes. Examples of “Browns” include dead or fallen leaves, twigs, wood chips, hair and fur, fireplace ashes, and even shredded newspaper, which contains cellulose from trees.
“Greens” in composting are nitrogen rich. Nitrogen acts as a vital protein source for the compost microbes, thereby accelerating the decomposition process. Examples of “Greens” include food and raw vegetable scraps, egg and nut shells, tea bags, green leaves, grass clippings, and coffee grounds.
Together, these reactants form the chemical process of composting, decomposing the food scraps you add to your compost pile.
When composting, it’s important to use a diversity of organic materials of varying sizes to maximize airflow for the microorganisms. Make sure there’s enough moisture for the microbes; compost piles should be comprised of 50 – 60% water. Without adequate water, the composting process leads to decomposition stalling as the microbes become dehydrated, which you don’t want!
Creating a successful compost is contingent upon having the correct materials to create an optimal environment for the decomposition process.
Composting at home & layering compost scraps
Residents can do their part to contribute to the SB 1383 organic waste reduction target by composting at home.
To ensure your scraps are working together to provide an optimal decomposition space for microbes, understand compost ratios and how to layer your ingredients.
To begin your own compost pile…
- Layer wood chips at the bottom of the pile to ensure proper airflow under heavy compost. Woodchips will also help absorb leachate, a natural liquid released during the compost process when water filters downwards.
- Create a 1:1 ratio of “Browns” and “Greens.” Make sure the pile is damp and not tightly packed; microbes rely on airflow to do their job!
- Place your “Greens,” which are high in nitrogen, on top of the wood chips.
- Add “Browns”, such as sawdust, on top of the food scraps as a good source of carbon.
- Cap the pile with more wood chips, which helps to neutralize and absorb odors.
- Be sure to give your pile a generous amount of water before you repeat the steps to layer.
If you are composting at home and keeping your compost bin inside, consider freezing your food scraps as they accumulate to ward off odor and fruit flies.
Life of a compost pile
Now that you’ve created your compost bin, how long do you wait before using the result? The composting process can take anywhere from 3-5 months to a year, contingent upon the method of composting.
Hot composting—a more proactive method—consists of turning and mixing your pile, watering as needed, and tending to the pile regularly. This level of care speeds up the decomposition process to conclude within 3-5 months.
On the other hand, cold composting—a less hands-on method—does not require you to turn your pile, allowing scraps to decompose naturally. This process can take up to a year.
Remember: A healthy pile will reach temperatures of 130° to 150°F, which will kill pathogens dangerous for humans and plants.
You’ll know your compost is ready when there’s mature compost. Characteristics of mature compose include an earthy smell, crumbly and loose structure, as well as a dark brown color.
Finished compost can be repurposed for a variety of uses. Use compost in your garden by incorporating it into soil, adding it to mulch, or combining it with potting mix for plants.
Composting in your community
Even if you don’t plan to compost at home, you can transport your materials to a composting center near you. Be sure to save “Browns” and “Greens” like those listed above.
If you’re looking to get started with composting, Paramount offers an array of resources.
One of the closest composting facilities is the Compost Co-op: Cortland Community Garden located at 7200 Cortland Ave, Paramount, CA 90723.
To learn more about Compost Co-Ops near Paramount, visit: https://www.lacompost.org/start-composting
To learn more about indoor and outdoor composting, visit epa.gov or CalRecycle.ca.gov.
For more information specific to LA County, visit: pw.lacounty.gov/epd/rethinkla.