Composting 101: How to Compost at Home
Learn what compost is, how to compost, what food scraps can be composted (and what can't) and how to use compost to enrich your garden soil.
Don't toss those food scraps-compost them! According to the U.S. Environmental Protection Agency, food waste accounts for almost 22 percent of all waste that goes into municipal landfills, more than any other single material in our everyday trash. Beyond keeping food waste out of landfills, composting has other benefits as well, turning food scraps and plant clippings into nutrient-rich soil. Some states and municipalities have moved to enact food waste bans in landfills and offer robust commercial composting programs that make it really easy for individuals to start composting.
But even if you don't have a commercial composting program available in your area, you can still compost at home. Backyard composting isn't as complicated or messy as you might think. By combining a few simple ingredients in the right proportions, you can be on your way to reducing food waste and creating a soil conditioner that benefits both your garden and the planet. Learn more about what compost is and how to start composting at home.
What Is Compost?
Compost is decomposed organic matter. It requires five basic ingredients:
- Carbon-rich materials ("browns"), such as leaves, straw, bark, paper, corn stalks, wood chips or sawdust
- Nitrogen-rich materials ("greens"), such as grass clippings, vegetable scraps or coffee grounds
- Microorganisms, such as bacteria, molds and fungi
Microorganisms, with the right amount of water and oxygen, break down carbon and nitrogen sources to create a final product that helps plants retain water and nutrients, and improves drainage and soil structure. Plus, turning yard and food waste into compost can greatly reduce your landfill contribution.
How to Compost
Add kitchen scraps and organic matter to your compost bin as needed, aiming for a carbon ("browns") to nitrogen ("greens") ratio of 25:1 to 40:1. Although microorganisms are available for purchase, you probably won't need them because they are almost always naturally present in the carbon and nitrogen sources.
Keep the pile moist-but not too wet, as this will hamper decomposition. Add sawdust to dry it or water to moisten it as needed.
Turn the pile with a rake or pitchfork regularly to help promote oxygen flow and release the heat that builds during decomposition-aim for a temperature between 90° and 140°F.
What Can Be Composted?
Any organic matter will decompose eventually, but for backyard composting, you want to only compost items that will decompose relatively quickly and that won't attract animals.
- Vegetable & fruit scraps
- Coffee grounds & filters
- Tea & tea bags
- Grass clippings
- Shredded newspaper
- Soiled cardboard, such as pizza boxes, ripped into small pieces
These items can only be composted in commercial facilities (not in your backyard compost):
- All food scraps, including animal products and bones
- Certified compostable products such as cups, utensils and takeout containers (look for BPI-Certified on the label)
What Can't Be Composted?
While composting is a great way to reduce waste, some items will do more harm than good. Avoid placing these in your backyard compost pile:
- Animal products such as dairy, bones and meat, which can attract pests (can be composted commercially)
- Oily foods such as mayonnaise, peanut butter, salad dressing or vegetable oils, which are difficult to decompose (can be composted commercially)
- Dog, cat and human waste, which can contain harmful pathogens
- Pesticide-treated yard waste, whose chemicals aren't broken down during the decomposition process
- Commercially grown cut flowers, which often contain dyes and chemicals
- Weeds and their roots, which can grow in the pile and spread wherever you place the compost
- Diseased plant material, which can spread the disease to nearby plants
- Bio-plastic products that are labeled biodegradable
How to Use Compost
Compost is ready when the pile no longer emits heat, is dark in color, and crumbles easily. At a minimum, compost will take several months to form. Using smaller pieces of carbon and nitrogen sources, ensuring consistent moisture, and turning the pile regularly can help speed up the process. Avoid using unfinished compost on your garden, as it can actually be toxic to plants.
- Mix compost into the top several inches of soil of your garden.
- Use as mulch around trees and shrubs.
- Use as a top-dressing for lawns.
- Use as a substitute for part of the soil in your container garden.
Do You Need to Use a Compost Bin?
You could just start a compost heap at the back of your property, but using a compost bin helps to retain heat and moisture, which will help with decomposition. It will also keep critters away from your food scraps. Compost bins vary widely in size, material and cost. You can purchase or build a permanent holding unit -or if you're just getting started, drilling holes 4 to 6 inches apart around a simple garbage can will suffice. Place your bin in a low-traffic area of your lawn where it will be protected from high winds.
Commercial Composting Services
If you're not interested in a DIY compost pile but still want to help reduce landfill waste, some municipalities offer drop-off or curbside composting. Simply place your compostables in a separate bin for pickup or drop-off along with your garbage and recycling. Some cities even offer residents the opportunity to pick up the completed compost for use in their gardens. Contact your municipality to see if such services exist, or search for private companies that perform similar services where you live.