Sustainable Composting: On Your Personal Pathway to Zero Waste

Half the garbage North Americans bury in landfills we could compost instead

North Americans could eliminate about half of what we send to landfills, by getting better at just one thing.

Is it recycling?

Nope, it’s composting.

It wouldn’t hurt to get much better at recycling, but that wouldn’t have nearly the same positive impact as composting. More than half of our garbage is food waste, yard waste, paper, wood chips, shavings and sawdust, and natural textiles, collectively called “organic waste” because it was once alive.

If we could get really good at composting, we would

• save money by doubling the available capacity of our existing garbage trucks and landfills,

• return valuable nutrients in our organic waste back to our soil,

• eliminate the methane problem in our landfills, which we cause by burying organic waste in them, and

• avoid the air pollution and ash disposal challenges of waste-to-energy facilities that burn organic waste instead of composting it.

Sustainability Step: Got Compost?

Here’s a practical sustainability step you can take on your pathway to zero waste: help your own family, organization, or neighborhood collect all your organic waste separately from non-compostable waste. Keep food scraps, natural fiber (including paper, cotton and wool), and wood waste separate from recycling (metal and glass) and plastic and synthetic trash that cannot be composted.

Composting is the most sustainable method for organic waste, encouraging the natural process of microbes enjoying warmth, water, and oxygen-rich air to break down organic matter back into carbon dioxide, water, and humus.

Humus is rich material in healthy soils that comes from organic waste.

Composting can happen at any scale, from a few scraps of paper to a huge pile of municipal waste, in any setting, from a rural farm to an urban apartment building.

My family spent a year in Japan, moving from a large, rambling old house in Maine with a large private back yard, to a tiny “50 tatami mat” apartment. Deprived of my backyard compost bins, I composted our food scraps in a balcony worm bin on the third floor of our apartment building. That’s a bit hard core (enlisting a horde of macro invertebrates—annelids and insects and mites, oh my!—to help the microbes) but shows that where there’s a will, there’s a way to compost.

Composting In Perspective

As humans sharing one finite planet, we are all on a shared journey to zero waste: reusing, composting, or recycling all the goods and materials we use.

In an earlier article, I reviewed the five major lawful methods (burying, burning, diverting, composting, and recycling) for handling solid waste and mentioned two unlawful methods (littering and dumping at sea). One type of solid waste, organic waste, is about half of our waste stream; broadly speaking, it includes anything that can be composted because it was once alive. (Some definitions of organic waste exclude paper for various reasons. But know that paper and cardboard are, in fact, made from fibers that living organisms grow.)

Organic Waste: Really More Than Half?
Most studies of composting facilities focus on food waste, which is only about a quarter of municipal waste. Adding paper and paperboard, yard waste, and wood, organic waste is more than half of the material being buried every day in landfills across North America.

We can choose to bury, burn, divert, or compost all of our organic waste, but much of it we can’t really recycle because it spoils and rots quickly when exposed to air, warmth, and water.

Put It Down the Garbage Disposal: Good or Bad Idea?
Putting food scraps down the garbage disposal turns solid waste into wastewater. In a future post, I’ll share my advice about whether that is a good or bad idea. The short answer: it depends.

None of your organic waste should end up in a garbage truck heading to a transfer station, landfill, or incinerator; all of it should be handled safely and beneficially in your own backyard or town composting facility. Unlike a sanitary landfill, which is designed to hold material in place for a very long time and keep most of it buried, a composting facility circulates air and water through organic waste as it is transformed in a natural cycle by a community of organisms that survive on the energy released.

Think of composting as a slow, wet, safe, and beneficial bonfire that never has an open flame. Oxygen and organic waste are consumed to produce carbon dioxide and water and give off energy, but at much lower temperatures than combustion requires. At the end of the process, instead of ash, you have humus: naturally decayed organic material that is a component of rich, healthy soil.

Composting saves time and money while preventing pollution and protecting public health. It can happen at the backyard scale, at a facility scale, or at a municipal scale. No permitting is required to build a backyard compost pile. Inspiring everyone to start composting at home would be like opening up twice as many landfills without taking any extra land, without requiring any site studies or engineering plans, and without using any roads or public infrastructure. If you could snap your fingers so everyone in North America does backyard composting, you could eliminate half of all garbage truck trips every day across our continent.

Weekly Poll: Do You Compost?

How to Compost

Understanding how and why organic materials spoil and rot allows us to control that process to our benefit. It all boils down to microbes: they do the work of composting. Our job is simply to feed the microbes things they can eat, keep them happy, and profit from their leftovers (humus) when they’re done feasting on our refuse.

I believe everyone on Earth should have a sustainable plan for our own garbage, taking responsibility for all the goods and materials we choose to use.

On the Front End

To compost well, the first thing to do is collect your organic waste in a thoughtful way. Tossing everything into one plastic garbage bag makes no sense if you plan to compost. The sustainability step is simple: keep your organic waste out of your garbage bags. I have volunteered for many Earth Day events, public fairs, eco festivals, and other gatherings where the organizers have overlooked this basic fact. Believe me, it’s no fun to rip open bags of trash to sort out what should be composted from what needs to go to the landfill!

Instead of putting your food and paper waste and your plastic waste together into one plastic garbage bag, here is what I recommend:

Separating your waste stream at the source makes composting much easier.

Use at least three different waste bins. If you really want to do the planet a favor, set up a seven-bin collection system that tracks with the seven back-end systems that actually process your solid waste if you live in a developed country. But at minimum have three different bins with clear markings: a brown square for compostable waste, a blue triangle for recycling, and a black diamond for trash that cannot be composted.

I picked these shapes and colors to make it easy for everyone to do the right thing. Consistency over time builds good habits. A brown square sticker on your compost pail with a note, “Food scraps and paper to compost,” a blue triangle on your recycling bin with a note, “Metal and glass to recycle,” and a black diamond sticker on your landfill trash bin with a note, “Plastic trash to landfill,” makes it easy to know at a glance which is which and what to do.

What to Do with Plastic, Polyester, etc.
I recommend having the wisdom to accept that plastic recycling is just not happening in the United States. Put clean, dry plastics and synthetics in the trash bin. Rinse off all food waste and let plastic dry before sealing it in a plastic garbage bag. It’s way more important to compost as much as you can. Focus your effort on getting all food scraps and soiled paper in a brown square compost bin and out of any black diamond trash bin.
Put nothing stinky in a plastic garbage bag, only plastics and synthetics that cannot spoil or rot! We can stash stable trash in sanitary landfills for a couple decades while an Artificial Intelligence figures out how to recycle post-consumer plastic waste in better ways than the problematic methods we’re attempting now. Storing plastic in a landfill is probably safer for public health than burning it for energy or shredding it for recycling.

Anything that is wet or stinky should go in a bin marked with a brown square; these bins need to be managed to minimize odors and vermin. It’s helpful to minimize the amount of stuff you put in your brown square bins so you can keep them to a manageable (small) size. It’s okay to put paper in with food scraps in your “brown square” bins, or you could choose to keep dry natural fiber waste in separate bins. Putting dry waste paper, paperboard, cardboard, and natural fibers (like cotton or wool) in a bin marked with a white square allows you to store large amounts of clean, dry organic waste until you’re ready to compost it.

Blue is the color for recycling. Metal and glass can be used over and over again indefinitely with no loss in quality. Paper fibers can be recycled about seven times before they need to be composted, buried or burned. For clean office paper and clean cardboard, you have a choice: recycle or compost. If you get paid for clean paper and cardboard, recycle them. But if you want to make more humus to enrich your soil and grow prettier flowers, compost them.

Save your back and your time by setting up a system that allows you to take out less garbage every week. Only your “brown square” bins have stinky, wet organic waste in them. Your black and blue (and white, if you decide to store paper separately) waste bins have dry material in them, so you can empty them less often.

On the Back End

In my backyard, I can compost almost anything without attracting rats because I have a high-end off-the-ground tumbling composter. A whole bunch of kitchen scraps go in (including meat, dairy, eggs, and seafood); a tiny bit of humus comes out.

When I sold composting equipment I’d advise customers that even if you collect every single scrap of food waste from a family of five for a year, you probably won’t produce as much humus as you’d like for your yard and garden. In my experience, for every gallon of kitchen waste, you get about a cup of humus. To cover the average-sized vegetable garden with two inches of humus per year, you’d need to collect and compost 748 gallons of kitchen scraps, or about two gallons per day.

If backyard composting isn’t your cup of tea, you may decide to hire a curbside composting service. Or find a farmer friend. Or perhaps your town has a municipal composting facility.

If you are willing to give backyard composting a try, I recommend that you find a friend who composts. Farmers and gardeners are good bets. Ask for their help to get you started. Chances are they will be delighted to take your extra food scraps off your hands as you get going if you start to get overwhelmed.

Many things can go wrong if you try to compost all your “brown square” waste. (And other things can go wrong if you try putting your “brown square” waste down a garbage disposal—especially if you have a septic system.) If you’re up for the challenge, however, it can be very satisfying to develop a backyard composting system that works well (including judicious use of a garbage disposal).

It actually helps the process to mix your “brown square” waste (a source of nitrogen) with “white square” waste (a source of carbon). To keep your microbes healthy, feed them the right ratio of available nitrogen to carbon, keep them warm, let them breathe lots of oxygen, and provide enough water. (A handy mnemonic is you W-A-N-T four things to make compost: water, air, nutrients, and temperature.)

Among composting experts, it’s convention to call stinky wet (high in nitrogen content) organic waste “greens” and dry non-stinky (high in carbon content) organic waste “browns.”

Why do I recommend “brown square” for food waste and “white square” for paper waste?

I just think people associate brown with muck and white with paper. If you collect “greens” in your kitchen, they’ll quickly turn brown. If you store dry white wastepaper in a bin, it will stay white. But feel free to change the colors to suit yourself!

Almost nothing can go wrong composting your paper waste. About the worst thing that can happen is that nothing happens. Shredding paper, keeping it wet, and mixing in a little dirt should get it to start composting fine on its own. But if you let your compost pile dry out, you’ll have a pile of shreds that just sit there. Don’t despair! Water the pile and stir it around with a big stick or a garden hoe. Maybe sprinkle in a compost activator. With enough water and direct contact with dirt, I’ve never seen damp shredded paper on the ground that didn’t start rotting eventually. (Although I have seen many big piles of shredded paper turn into little piles of shredded plastic tape and labels, paper clips and staples—if these contaminants bother you, be careful what you put in your “white square” bins for paper compost.)

When you compost successfully, you’ll end up with beneficial humus for your yard and garden, starting the cycle anew by giving plants better soil.

Good luck in your composting adventure, and thank you for doing your part to help us reach a sustainable future with zero waste!

Questions?

I’ll be writing up a short hands-on guide to composting to go into more details about exactly how to compost, with tips and tricks based on twenty-five years helping thousands of people compost better. (It’s true: over years of running a sustainable living store on Maine Street in Brunswick and volunteering with the composting team at the Maine Organic Farmers and Gardeners Association’s Common Ground Fair, I have literally talked with thousands of people about composting.)

If you still have questions after reading all this, did you know that Substack provides a sneaky way for you to ask them? You can leave a comment!