How to Compost

Medically Reviewed by Melinda Ratini, MS, DO on August 12, 2021

Do you toss fruit peels, coffee grounds, and plant clippings in the trash? Many of your kitchen and yard waste items can be recycled into compost.  

Compost is organic material that has decomposed. The composting process involves:

  • Organic matter like plants — if it can be eaten or grown in a garden, it can be composted
  • Moisture
  • Bacteria and other microorganisms, which break down the organic matter 
  • Oxygen  

Compostable organic materials are divided into:

  • Browns. These are woody materials that have a lot of carbon. Browns can include dead leaves, twigs, and bark.
  • Greens. These are the compost’s source of nitrogen. Greens include grass and kitchen scraps. 

Reduces waste. About 68% of the wasted food in the U.S. ends up in landfills. That’s about 42.8 million tons a year. Composting turns your kitchen scraps into an environmentally beneficial product.

Having less food waste also means that fewer carbon emissions are spent on hauling away trash.

Reduce greenhouse gas emissions. It’s estimated that about 8% to 10% of global greenhouse gas emissions is produced by food waste.

When you compost, you help to reduce methane gas emissions from landfills.

Improves soil. Adding compost enriches soil, adding nutrients and microorganisms. It also helps prevent soil erosion by reducing runoff. 

Compost also reduces the use of fertilizers and pesticides. Compost adds nutrients to the soil and helps prevent plant diseases and pests. 

The first step is to collect your organic materials. Keep a small container on your kitchen counter to collect your scraps. You can take this out to your compost bin every day or when it's full. 

The easiest way to compost is to build a pile on the ground or in a bin, and let it sit. It takes at least 6 months to 1 year to turn into compost. This is known as cold or slow composting.

To create compost faster, you’ll need to follow these steps:

  1. Build your compost pile in layers. Start with browns and alternate with greens. The smaller your materials, the faster they will compost. 
  2. Water each layer as you add it.
  3. Turn your compost pile regularly. This is how you supply oxygen. Move the materials from the center to the outside, and vice-versa. If you turn it every day, your compost will be ready in about 2 weeks. If you turn it every week, it will take 6 to 8 weeks.

What if you live in an apartment or don’t have enough outdoor space? You can easily compost indoors, too.

Composting indoors or in containers is different because the environment doesn't have all the elements needed. You’ll need to bring these in to help start the process.

Composting with worms (vermicomposting). This takes up very little space and can be done indoors. You can use a premade worm composting container or make your own: 

  1. Get an 8 to 12 gallon plastic storage bin. 
  2. Drill several holes in the top, sides, and bottom. 
  3. Wet some shredded newspaper for bedding. 
  4. Start with 1 pound of red wiggler worms.  
  5. Feed your worms with food waste. Don’t give them meat products. 
  6. Keep the bin away from extreme temperatures.
  7. After about 1 month, your compost should be ready. 

Bokashi. This indoor composting method requires a yeast and bacteria solution. You can buy it online or make your own. Bokashi composting is done in a sealed container. There’s little odor, and it takes up little space. 

Not everything is compostable. It’s important to keep certain items out of your home compost bin. But if your city has a composting program, check to see if they accept these items.

These items may attract pests and create odor problems with your compost:

  • Fat, lard, grease, and oils
  • Dairy products like yogurt, butter, and milk
  • Eggs
  • Meat or fish bones and scraps

These items may contain substances that are harmful to plants:

  • Leaves or twigs from the black walnut tree
  • Charcoal or coal ash
  • Plants that are diseased or have insects

Other items that don’t go into your compost bin include:

  • Pet wastes like dirty cat litter and poop. Pet wastes may contain parasites, bacteria, and viruses that are harmful to humans. 
  • Plants and other yard waste treated with chemical pesticides. These may kill any useful composting organisms.

Here's how to use your compost:

  • Add compost to soil in vegetable gardens, flower beds, and other plants.
  • Use it as mulch. This helps reduce moisture loss from the soil. Apply a 3-inch layer of compost around flower beds, vegetable gardens, or around trees or shrubs.

Show Sources


K-State Research and Extension: “Composting in the city,” “The Basics of Vermicomposting: Composting with Worms.”

OSU Extension Catalogue: “How to Use Compost in Gardens and Landscapes.”

UC Master Gardener Program of Sonoma County: “Composting Basics.”

UN Environment Program: “How composting can reduce our impact on the planet.”

United States Environmental Protection Agency: “Composting At Home,” “Reducing Wasted Food At Home.”

University of Illinois: “The Composting Process.”

USDA Natural Resources Conservation Service: “Composting.”

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