Picture this: You just finished eating dinner at a friend’s house. They ordered the takeout so you’re cleaning up, and there are a few bits of broccoli and chow mein at the bottom of the (allegedly) compostable containers. Now you’re standing in their kitchen, staring at their trash, recycling, and compost bins. You look at the container, the napkins, and the chopsticks — you panic, close your eyes, toss everything in the compost bin, and hope for the best. 

The answer to “can I compost this?” isn’t always straightforward. While most of it is intuitive, there are a handful of important compost do’s and don’ts. Fortunately, a little research and reading can help you figure that out. Let’s get into it. 

What you can — and can’t — compost in your backyard

There are two primary categories of ingredients for a home compost pile: greens and browns. Greens refer to most of the organic material that’s home-compostable, which, of course, includes food scraps. Think: coffee grounds, fruit and veggie scraps and peels, and those bananas that might be too brown to even make banana bread with. 

There are also some things that fall into the green category that you should avoid composting at home, even in small amounts, because they’re likely to invite bad smells, along with flies, rats, and other unwelcome pests into your finished compost pile. So be sure to avoid adding meat, poultry, fish, and dairy byproducts.

Browns are things that are usually (but not always) brown and tend to be very carbon rich material — think dry leaves and twigs. Cardboard boxes, shredded paper, paper towels and tissues are all also considered home-compostable browns. While there are some non-food items that fall into the greens category (like garden trimmings, grass clippings, and other non woody and wet yard waste), most non-food items that are compostable at home fall into the brown category. 

And just as with greens, there are some browns that you should avoid composting at home. Large amounts of evergreen leaves and nettles, large branches, colored paper, and waxed cardboard (that means: compostable serveware, such as coffee cups) can’t be composted at home. 

Do compost:

1. Fruit scraps

2. Raw vegetable scraps, peels, etc

3. Coffee grounds

4. Dry leaves

5. Twigs

6. Shredded paper or cardboard

7. Paper towels

8. Grass clippings

Don’t compost:

1. Meat 

2. Poultry

3. Fish

4. Dairy

5. Cooked food

6. Waxed paper 

7. Colored paper

8. Large branches

Using a food recycler

A Mill food recycler complements home composting by pre-processing your food scraps and allowing you to compost more of the no-no items above in your backyard pile, including meat and dairy. That’s because the Mill heats them enough to kill any potential pathogens and shreds them into tiny pieces — making them less attractive to unwanted visitors to your pile.

With Mill, you’ll still want to avoid tossing in compostable plastics and take-out containers, as well as large bones. But that leftover chicken, uncooked bacon, and too-funky cheese are all welcome. As are leftovers or take out- cooked foods are fine — but only if you forget to eat them first. By following a few simple steps, you can significantly reduce food waste at home, making Mill an even more powerful tool in your kitchen. 

What you can compost via a commercial-scale compost program

Most commercial-scale composting programs are flexible, and they can handle the browns and greens that at-home operations can’t. 

Commercial operations can usually welcome meat, dairy, cooked foods, bones and bioplastics. They can also handle things like compostable takeout containers covered in food and more difficult-to-get-rid-of things like oyster and clam shells you have left over from that big seafood boil. 

Of course, each service provider is likely to have slightly different guidelines about what they can and can’t accept, so make sure you check their guidelines before you go tossing every scrap you’ve got into your city-provided bin.

Sources:

1. Recology: “What Goes Where.” https://www.recology.com/recology-san-francisco/what-goes-where/

2. New York City Department of Sanitation: “Food Scrap Drop-Off.” https://www.nyc.gov/site/dsny/collection/residents/food-scrap-drop-off.page

3. CNBC: “Chipotle Wants You to Think Composting Before Burrito Bowl Becomes Trash.” June 18, 2023. https://www.cnbc.com/2023/06/18/chipotle-wants-you-to-think-before-tossing-your-burrito-bowl-in-trash.html

4. Sweetgreen: “Announcing Sweetgreen in Schools.” https://impact.sweetgreen.com/