Several options exist for residents wanting to compost at home. For an indoor option, composting with worms is possible. Residents with outdoors space can start a backyard compost pile.
What is composting?
Composting is a controlled natural process in which microorganisms convert organic material (food, wood, and yard waste) into soil-like material, known as compost. Compost is not soil or dirt; it’s a soil amendment or additive, like a fertilizer. When added to soil, compost helps to improve soil health, conserve moisture, prevent erosion, and reduce weed growth.
Success in composting depends upon sufficient moisture and oxygen and proper amounts of carbon and nitrogen. Carbon-rich materials include leaves and wood. Nitrogen-rich materials include grass clippings and food waste.
What is the difference between backyard composting and the Compost Facility’s composting process?
Backyard composting is small-scale and commonly in residential areas. In Iowa City, some materials are not allowed to be composted in a backyard system because they easily attract animals and emit odors.
The Compost Facility, located at the Iowa City Landfill (3900 Hebl Ave. SW), is a commercial-sized operation, processing thousands of tons of organic material per year from residential and commercial customers in Johnson County.
Materials that are okay to compost in an at-home system:
- Yard waste including leaves, grass clippings, plant/shrub trimmings, garden trimmings
- Food waste including coffee grounds, and fruit and vegetable peels
Materials that should not be composted in an at-home system:
According to the Iowa City Code, the following materials are not allowed in compost piles. These materials easily attract animals and emit odors and should be avoided:
- Meat and bones
- Dairy products
- Fats
- Grease
-
Oils
-
Raw manure
Choosing a container:
To prevent materials from blowing away, a container or enclosure of some sort must be used. Container examples:
- Flexible wire panels
- Bricks or cement blocks
-
Wood frames
-
Plastic bins
- Tumbler bins
Location of compost pile:
Iowa City Code lists the following requirements for the placement of a compost pile:
- Should be screened from street view in a confined area no larger than 25 square feet in area.
-
Should be located no less than 20 feet from a house and at least 5 feet from a property boundary line or any wood structure, excluding fences.
-
Should not be located in a drainageway or in an area between a building and the street right-of-way.
Building a compost pile:
-
Start the pile with a layer of coarse material like branches and twigs to allow air flow to the pile.
-
For a carbon source, add 6 inches of leaves and other woody materials. For a nitrogen source, add 2-3 inches of grass clippings, food waste, and garden trimmings. Mix these two layers to speed up decomposition and then cover with 2 inches of dirt to control odors.
-
Dampen the pile with water as new layers are added or more frequently if the weather is dry. The pile should be concave in the center to prevent runoff of water. The moisture content is sufficient when the surface of the pile glistens.
-
To speed up decomposition, mix/turn the pile once a week and periodically sprinkle it with water to keep it moist.
-
When the interior of the pile is no longer hot and the material has broken down into dark, crumbly soil, the composting is finished. This process usually takes 3-6 months.
Using finished compost:
According to the Environmental Protection Agency (EPA):
"You can add compost to your flower and vegetable beds, window boxes, and container gardens; incorporate it into tree beds; mix it with potting soil for indoor plants; or spread it on top of the soil in your yard.
Compost can be used as a soil amendment or as a mulch. As a soil amendment, mix in two to four inches of compost to the top six to nine inches of your soil. As a mulch, loosen the top two to three inches of soil and add a three-inch layer of compost on the surface, a few inches away from plant stems and tree trunks.
Adding finished compost to your soil:
- Improves the structure and health of your soil by adding organic matter.
- Helps the soil retain moisture and nutrients.
- Attracts beneficial organisms to the soil and reduces the need for pesticides and fertilizers.
- Reduces the potential for soil erosion.
- Sequesters carbon in the soil.
- Builds resiliency to the impacts of natural disasters."
For more information, visit the EPA web pages:
For more information, email recycling@iowa-city.org or call 319-887-6110.
