What is composting?
Composting is a process by which organisms break down organic materials (e.g. food scraps, leaves, lawn clippings, etc.) into smaller sizes and in the form of nutrients that can be taken up by plants. In forests, leaves and woody debris naturally break down by the actions of insects and other invertebrates, bacteria, and fungi to form the upper layers of the soil. Composting is the same process.
The benefits of compost
Compost can be used to fertilize plants, to aerate the soil, to provide better soil structure, to encourage soil organisms that help provide nutrients to plants, and to help hold moisture in the soil. Compost can also be used in erosion control by limiting soil loss and by promoting the growth of plants that stabilize the soil.
How and what to compost
All organic materials (anything made from once living organisms such as wood, plant materials, meat, or animal fibers) can be composted. Some materials may be problematic for home composting. For example, oils, fatty products, and dairy products may slow the process and create odors or attract pests in backyard composting systems. Meat, bones, and seafood have their own problems as compost piles with these items can attract pests and require temperatures that exceed 131 degrees Fahrenheit to kill pathogens that may be lurking. See the table below for more specific examples of compostable items. These materials can be sent to commercial composting facilities that have the capability of breaking these materials down. When you bring your food scraps to a transfer station or place in a container for pickup at your business, apartment building, or school, those materials can be added – but not to a home composting container. If you compost at home, you can still throw away meat, bones, fish, and grease after July 1, 2020. Alternatively, use a solar digester or take meat scraps to a transfer station.
What and what not to compost at home:
- Fruits and vegetables
- Coffee grounds and filters; tea bags
- Nut shells
- Paper, including shredded newspaper and cardboard
- Grass and yard trimmings, leaves, hay, and straw; houseplants
- Wood chips and sawdust
- Fireplace or wood stove ash
- Cotton and wool fabrics including vacuum and dryer lint (but not lint containing artificial fabrics)
Composting at home
You can divide the materials you compost into “greens” and “browns.” Greens are high in nitrogen and are generally wet. Vegetables, fruit scraps, grass clippings, coffee grounds and tea bags are all greens. Browns are dry and include leaves, straw, hay, wood chips, dried grass clippings and paper and provide needed carbon. Browns provide needed carbon. A general rule of thumb is to evenly mix greens and browns.
You can use a compost bin, as in the picture on the right, or a simple pile or fenced-in area using wood pallets as shown below. You can put a great deal of effort into composting by maintaining the correct blend of materials, keeping the pile turned to get oxygen into the mixture, and maintaining a temperature of 120 to 140 degrees to kill pathogens and speed up decomposition. Or you can be more casual and let nature take over with minimal maintenance. Decomposition will occur more slowly, but you will successfully recycle your organic materials. As they say, “compost happens.”
The typical size of a compost pile is 3’ x 3’ x 3’ or one cubic yard. The size needs to be based on how much material you need to recycle and how much effort you can expend maintaining the pile.
Water is essential, so you should monitor moisture periodically by grabbing some material and squeezing it. If a few drops of water fall, that should be sufficient. More and the pile is too wet; and less and it is too dry. One advantage of a closed bin is that the cover will limit water input from precipitation. Alternatively, you can cover your open pile. In either case the piles should be well drained.
Air is essential as the organisms that are doing the composting need air to survive. If the pile becomes too dense or wet, those organisms die and organisms that can function in low or no oxygen conditions thrive. Decomposition slows and the pile will begin to smell. The pile needs to be turned weekly or as needed using a fork or your hands or whatever tool is best for you.
There are many organisms involved in composting including nematodes, springtails, various mites, earthworms, millipedes, bacteria, and fungi. They all need materials, air, water, and the right temperature to thrive.
Common problems include odor and pests. The table below provides some solutions.
|Bad smell||Not enough air|
Too much moisture
|Turn the pile
Add dry materials
|Pile will not get hot||Not enough moisture|
Pile is too small
Lack of nitrogen
Pieces of material are too large
Enlarge the pile
Chop up the pieces
|Rodents, flies, pets are problematic||Pile contains meat, bones fatty materials||Alter what is in the pile. Bury fruit and vegetable scraps in the middle of the pile|
|Pile has slugs||Slugs are accessing the pile||Separate the pile from the garden or other source of slugs after you remove them from the pile|
Sources for more information
The following are some websites that offer more information on composting:
Chittenden Solid Waste District: Backyard composting
This site describes how to get into composting in six steps. CSWD also offers workshops on backyard composting.
Vermont Agency of Natural Resources Composting
You can find more information on composting operations, rules and regulations in Vermont as well as links to informational sites.
University of Vermont’s Master Composter Program
A Master Composter Certification program offered online twice a year.
The Dirt on Compost
A downloadable beginner’s guide to backyard composting.
Basic Compost Recipe:
2-3 Parts Carbon (Browns)
Woody, dry materials: sawdust, wood shavings, leaves, soiled paper, shredded paper, straw
1 Part Nitrogen (Greens)
Green, wet materials: food scraps, grass and garden clippings (no weeds), manures (no cat or dog)
Add to gardens and lawns for vital nutrients and reduce drought.
- Shovel or pitchfork, or a bobcat/tractor for large piles.
- Covered area for storing carbons/leaves.
- Thermometer if doing “hot” composting with larger pile.