Organic material makes up about 58 percent of what Denver residents send to the landfill every year. These items can be composted, which is the controlled decomposition of organic materials by microorganisms. This process results in compost, a crumbly, earthy-smelling, nutrient-rich, soil-like material.
Compost contains both carbon and nitrogen sources, which can be simplified as browns for carbon (e.g., leaves, straw, woody materials) and greens for nitrogen (e.g., grass and food scraps). Adequate sources of carbon and nitrogen are important for microorganism growth and energy.
Organic materials are broken down through the activities and appetites of various invertebrates that will naturally appear in compost, such as mites, millipedes, beetles, sowbugs, earwigs, earthworms, slugs, and snails. These microorganisms need adequate moisture and oxygen to degrade the organic materials in the most efficient manner.
Microbes in the pile create considerable heat and essentially "cook" the compost. Temperatures between 90 and 140 degrees Fahrenheit are common in properly maintained compost piles, but may not reach these levels in backyard compost piles. These high temperatures are necessary for rapid composting as well as for destroying weed seeds, insect larvae, and potentially harmful bacteria. When the compost is finished, it has a crumbly texture throughout the pile.
Vermicomposting is a method of composting that uses a container of food scraps and a special kind of earthworm known as a red wiggler. Over time, the food is replaced with worm droppings, a rich brown matter that serves as an excellent natural plant food. For more information on what to feed worms and a list of worm vendors visit the page Bins for Home Composting.
If you supply the proper conditions (volume, surface area, moisture, air and variety of materials), you should have little difficulty maintaining your compost system. Occasionally, though, problems occur in any biological system. They usually can be dealt with fairly easily by following these tips:
Compost is ready to use when it is dark and crumbly. You should not be able to recognize most of the materials, and it should smell like a damp forest floor.
Worm composting (or Vermicomposting) recruits red wiggler worms to convert our non-meat food scraps into nutrient-rich compost that can be used to improve the health of our yards, gardens and houseplants. See detailed information on how to start composting with worms (pdf).
The greater the variety of material used, the better the casting (compost) will be.
A composting bin is a great way to control and accelerate your backyard composting efforts. You can build your own or buy a pre-made composting bin.
For instructions on how to build several different types of backyard composting bins,CLICK HERE.
For more information about composting, call Denver Recycles at
3-1-1. We can offer additional resources, and provide information about composting classes.
Browns and Greens Make Gold! A Guide to Backyard Composting (English/Spanish)
Worms Are Our Buddies (English/Spanish - 348 KB)
Grasscycle (English/Spanish - 632 KB)
Sign Up Today!
All classes are free, but participants must register at least one week in advance so the class can be properly staffed. To sign up, visit dug.org/compost or call 303-292-9900.
Classes are held at the Denver Compost Demonstration Site located in the Grove Community Garden at 13th Ave. and Colorado Blvd.
* WW = Worm Workshop – this class focuses on worm composting techniques.
* BP = Build-a-Pile – this class gives participants hands-on experience in building a compost pile, including incorporating different materials, chopping ingredients, watering and turning the pile.