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How to Compost Indoors

Medically Reviewed by Poonam Sachdev on January 05, 2023

Composting is a great way to reduce waste and give back to the environment. However, not everyone has the outdoor space for composting, but that doesn’t mean you can’t compost. There are a few different methods to choose from if you want to compost indoors. 

How Does Composting Work?

Composting is a method of taking organic waste, like food scraps and yard trimmings, and turning them into nutritious fertilizer.

Composting works by creating the ideal environment for decomposing organisms, such as bacteria, fungi, and worms, to thrive. These organisms break down the organic waste, and what’s left is a compound high in vitamins and minerals that you can add to the soil to help plants grow.

For composting to be successful, the conditions need to be just right. The compost pile must have the right materials, the right amount of air and water, and the right temperature.

You can only compost organic waste. This means it needs to come from something that at one time was alive, like a plant or animal. Your compost pile needs to be a mix of high-carbon (brown items) and high-nitrogen (green items) materials. 

Brown materials include items like dead leaves, dried grass and plants, twigs and branches, and newspaper. Green materials include food scraps, grass clippings, and coffee grounds.

What Are the Benefits of Composting?

Organic matter makes up a large portion of our waste stream, about 28% of what we throw away. The cost to get rid of this waste is high not just in a financial sense, costing billions of dollars every year, but it’s also costly to the environment. To help the environment, we can recycle the organic waste we produce at home through composting.

Landfills also create conditions for anaerobic decomposition. This type of decomposition produces a biogas that's about half methane and half carbon dioxide. As both methane and carbon dioxide are greenhouse gasses, the biogas released from anaerobic decomposition is harmful to the environment. Through composting, we can help cut greenhouse gas emissions generated from landfills.

Composting is also important because it helps the soil retain water. When soil naturally retains water, less water has to be spent watering crops and plants. Even a 1% increase in organic matter helps the soil retain an extra 20,000 gallons of water per acre. When soil retains water, it’s also less likely to erode.

What Is Indoor Composting?

Most of the time, composting is done in piles or bins outdoors. There are a few benefits to an outdoor pile, such as the ease of adding yard waste, open air in case it starts to smell, and the ability to store more. However, that doesn’t mean composting is out of reach if you live in an apartment or in an area where the weather isn’t good for composting.

You can try an indoor compost system. These are usually smaller but allow you to keep your compost inside. Some can even fit on your countertop! Depending on your preference, you can try a few different indoor composting methods.

Vermicompost. Vermicompost, or composting with worms, is the most common type of at-home composting. You can purchase a worm composter or make one yourself. This type of composting is best for food scraps.

Electronic composting device. An electronic composting device is not technically a form of composting, but more of an indoor composting alternative. These devices dry out your food scraps, then grind them down. However, the resulting product won't have all the nutrients of traditional composting. 

You can either throw it in the trash, and though it will go to a landfill, it will decompose much faster than food scraps normally would. Otherwise, you can add microbe tablets to boost the nutrients so you can add the dried food scraps to the soil.

Compost collector. If the idea of keeping a compost bin indoors isn’t for you, look for a bin or caddy that lets you compost your food scraps. Many areas have a composting pickup service, or you can bring your container to a place nearby that takes composting materials. This allows you to keep your scraps out of landfills, even if you don’t have the space or stomach for traditional composting.

How to Compost Indoors

If you opt for vermicomposting, you can purchase a vermicomposting container or make one yourself.

1. Make the container from a plastic or wooden bin. Avoid metal, as this can make the temperature inside too extreme for the worms. 

2. Make holes on the side for ventilation and on the bottom of the container for drainage. Because there will be liquid draining from your bin, you’ll want to put it inside a larger bin or on a tray.

3. Make bedding for the worms from carbon-rich materials, like strips of paper or dried leaves. 

4. Get the bedding wet and squeeze out the excess water, so it’s about the dampness of a wrung-out sponge. 

5. Add bedding to the bin. Fill your bin with bedding about two-thirds of the way up. 

6. Add the worms. The worms that are ideal for vermicomposting are Eisenia fetida or “red wigglers." You can buy these online or sometimes at pet stores or stores with garden centers. 

About one pound is a good starting place. One pound of red wigglers can eat through three and a half pounds of food scraps per week. 

7. Add food scraps like fruits and vegetables, bread and grains, and coffee grounds. Avoid meat, dairy products, and foods cooked in oil because these attract pests. 

To feed the worms, move some of the bedding to the side and add the scraps. Then cover the scraps with more bedding. Each time you add food, try to do it in a different part of the bin.

How to Harvest Your Compost

Once your indoor compost bucket is nearly full, it’s time to harvest the compost. The easiest way to do this is to move all the contents to one side of the bin and then add new, moistened bedding to the other side. 

Start adding food scraps to the new side. About a month later, the worms and critters will migrate to the new side. You can then scoop out the compost.

Show Sources

SOURCES:
Consumer Reports: “How to Compost in Your Apartment.”
Natural Resources Defense Council: “Composting 101.”
NYC Compost Project: “Indoor Composting with a worm bin.”
Sierra: "Composting 101: Hooray for the Black, Brown, and Green."

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