Published: Dec. 15, 2023 By

hand digging in soilCompost is the natural process of recycling organic matter into a nutrient-rich fertilizer. It is a significant part of the waste system that aids in fighting the climate crisis. Composting is more popular today as information about the benefits has spread to the public.  The positive environmental effects make it an appealing habit to adopt.  

What is compostable? 

Compostable products become natural elements like carbon dioxide, water vapor and organic material. Compost facilities provide an ideal environment for bacteria, fungi and other decomposing organisms to break down biodegradable items. All compostable materials are biodegradable, but not all biodegradable objects are compostable. Understanding what you can and cannot compost on campus and residentially is essential. 

In spring 2023, Colorado’s composting guidelines changed. Previously, CU Boulder offered compost bins all over campus and accepted compostable paper towels, plastics, food scraps and yard waste. With the changes, CU Boulder continues to compost food scraps and yard waste from campus operations. These were the majority of the items composted from our campus before the change. In 2022, CU Boulder composted approximately 23 tons per month of yard waste and 40 tons per month of food scraps.  

In Boulder, curbside compost pickup is available for residents at no extra charge. The same changes that impacted campus composting also affected the city of Boulder. Residents can only compost food and yard waste. 

The impact of composting on the environment 

The main benefit of composting is that it helps reduce waste in landfills. When food scraps go into landfills, they generate methane, which has a global warming potential 84 times more potent than carbon dioxide. But when those food scraps are instead composted and applied to our soil and land, compost sequesters carbon. 

40% of residential waste found in landfills is compostable. By composting, you help extend the life of landfills. Compostable materials such as food waste and paper decompose anaerobically (without oxygen) in a landfill, producing methane (CH4). Composting proves to be an effective way to reduce greenhouse gas emissions.  

Composting also helps conserve our natural resources, like water. It helps retain most of the soil’s moisture, so you use less water. Compost can lead to a significant reduction pesticide use, thus reducing further emissions that are associated with them.  

Composting improves soil by reducing soil erosion and retaining nutrients. It increases soil fertility and converts nitrogen into a more stable form and phosphorus into a less soluble form. Using compost grows stronger, healthier plants and overall garden. Healthy soils are essential for protecting watersheds. 

Composting at home 

You can create compost to use in your backyard, patio or container garden. 

Open pile composting steps: 

  1. Either build or buy a compost bin about one cubic yard in size (3 ft x 3 ft x 3 ft). You can purchase composting bins from local hardware or big box stores. Note that size is important to achieve the proper temperature. 

  1. Try building your pile in a shady spot to reduce the need to add water. 

  1. Mix two parts brown, like small twigs, straw or dry leaves, with one part green, like grass clippings or kitchen scraps. This ratio provides a good mix of carbon from the brown materials to nitrogen from the green materials. 

  1. Make sure everything you add is relatively small since materials will break down at a quicker rate. 

  1. Water your compost just enough to get it a bit moist. Ecocycle suggests keeping compost at the wetness of a “wrung-out sponge.” Check the moisture levels by picking up a handful of the mixture and feeling its moisture. 

  1. Maintain the compost by adding fresh materials at least once a week. Mix and water the compost weekly. 

  1. If fruit flies become a problem, keep a plastic sheet or a piece of old carpet on the surface of the compost bin. You can bury fresh food scraps under bedding or consider buying a container with a lid. 

  1. After adding to your compost pile for a few months, the resulting product should be rich, dark soil. 

  1. Use end product for potted plants, filling in spots on your lawn, landscaping in gardens or more. 

  1. Do not add bones, meat, cheese and other dairy products since these won’t break down in backyard compost piles. 

Worm compost (vermicomposting) steps: 

  1. Secure a large bin with a lid. 

  1. Use a drill to create holes in the sides at the top of the bin. 

  1. Store the bin in a sheltered location, preferably at 55 to 85 degrees Fahrenheit. You can also locate the container inside a shed or garage, as it won’t smell. 

  1. Use a combination of shredded newspaper and some native soil to start a fresh bin. Shredded cardboard, stray, dry leaves and other scrap paper also works. 

  1. Add worms by digging a little hole in damp bedding. The most common worms for composting are Eisenia Fetida, also known as red wigglers. For a 35 gallons bin, add about one or two pounds of worms, approximately 1,000 to 2,000 worms. Worms can eat their body weight in food waste per day. 

  1. You can add all food scraps except for meat and dairy products. Always bury the food after adding it. 

  1. Stir all contents of the worm bin, careful not to kill the worms. 

  1. Make sure the bin is always slightly damp but never soggy. 

  1. Use the worm castings as fertilizers and soil boosters around your yard and garden! 

  1. Use the “worm juice” from the bottom of your bin to water your plants. 

Industrial composting 

CU Boulder uses industrial composting through a partnership with a service provider. Industrial or commercial composting is large-scale composting designed to handle a high volume of organic waste. The compost can be sold to farms, plant nurseries or individuals, depending on the facility. 

A typical industrial composting operation collects waste from grocery stores, restaurants, campus communities, green waste bins collected from households and other commercial facilities with compost bins. Many facilities work with garbage and recycling agencies to make composting easily accessible for individuals. 

Contamination is a massive problem for industrial composting sites. Similar to recycling plants, nonbiodegradable garbage is a common contaminant. Separating these items can be messy and inefficient, but not doing so heavily decreases the soil quality produced. Facilities are working on better, more efficient ways to sort through the compost they receive.