Congratulations! You’ve taken the step to start composting. Whether you have a pile in your backyard, or you take your kitchen scraps to your local farm or waste center, we bet you’ve wondered—what exactly can and can’t go in your compost? The answers may surprise you!

Compost is an integral part of a regenerative organic farm or garden. Composting provides a diversity of microorganisms and nutrients that encourage healthy plant growth and development when incorporated into soil. Created from the aerobic decomposition of waste materials, we usually think of compost consisting of vegetable waste or grass (nitrogen-rich material called “greens”), and some leaves or straw (carbon-rich material called “browns”).

But could you be composting more in your backyard? We asked you (our followers!) for the things you always wanted to compost but were too afraid to ask about. Our Farm Director and resident Master Composter, Rick Carr, gives you all the dirt!

Question: Cheese and dairy products
Answer: Yes!

“These products can be composted in any backyard composting system,” said Rick. While they will decompose like the other “green” material in your compost bin, make sure to keep them well covered with “brown” material like leaves or straw. This helps prevent odors, pests, and flies. While dairy products can be composted, it may not be the best choice if you’re a beginner composter.

Question: Ice cream containers
Answer: No!

You may think these cardboard containers would be naturals for the compost pile, but they hide a sneaky secret! “Ice cream containers are lined with a thin film of plastic, which does not decompose,” Rick explained. “When you turn your compost, you’ll find sheets of plastic after the rest of the container has broken down.” Opt for putting these containers in your traditional garbage instead.

Question: Cooked foods like meat, rice, etc.
Answer: Yes!

It’s a myth that adding anything but raw vegetables to a compost pile will result in a stinky mess that will harm your garden. “Treat all food wastes the same,” said Rick. “No food showing—be sure to keep them covered with your brown material. Otherwise, you have a greater chance for angry neighbors.” Like dairy, wait to compost meat and cooked foods until you have more experience with your system.

Question: Whole Eggs
Answer: Yes!

Eggshells are a staple in compost piles everywhere—besides our veggie waste, it might be the first thing we think to compost! But did you know you could also compost whole eggs? “You can put in the whole egg, but they will compost faster if they’re cracked open first,” said Rick. While it’s always better to eat your eggs than to compost them, if you have spoiled eggs or no other method to use them, throw them in the compost

Question: Coffee Grounds
Answer: Yes!

Coffee grounds are perfectly acceptable for compost piles—so keep your compost bucket close by for your morning cup of joe! “You can also compost coffee filters, so empty the whole basket of a traditional coffee maker into the compost,” said Rick. However, single use coffee pods and other methods of caffeination are not compostable (and are not even recyclable in most states!).

Question: Baby wipes
Answer: No!

Almost all paper breaks down in a compost pile—so why wouldn’t baby wipes? “Something about the material that baby wipes are made out of prevents them from decomposing,” explained Rick. If you’re looking for a low waste baby hygiene option, reusable cloths and diapers may be a better choice.

Question: Fireplace ashes
Answer: Yes!

“Yes, but not heavy loads,” said Rick. “Fireplace ashes are okay from time to time. Too much ash will reduce pile porosity and oxygen availability to microbes,” a fundamental aspect of the aerobic decomposition process.

Question: Compostable bio-plastic consumer products (plates, flatware, bags)
Answer: No!

This one is the most surprising to everyone, according to Rick. These materials are only able to break down at industrial compost scale, something that’s inaccessible to most backyard composters. Even when these materials do break down, these bio-plastics turn into a sticky substance that provides nothing to the compost or the soil it’s put on. Instead, go for sustainable materials like bamboo plates and cutlery, or use regular plates and silverware that can be washed and reused.

Did we miss something? Drop us the one thing you’ve always wanted to compost, but were too afraid to ask about, in the comments below!

Want to learn more from Rick Carr about composting? Check out our new backyard composting Youtube series! Rodale Institute also hosts workshops, webinars, and more about composting, and visit our downloadable resources section for how-to guides and more.

Rodale Institute’s Organic Field Day will be held at our Kutztown, PA headquarters on July 23, 2021. Attendees can learn more about composting, as well as our research programs, farmer training, and more, at this annual, interactive event.

Can’t come in person? Register for our 2021 Virtual Field Day instead!

For more updates on our research and programming, follow us on FacebookInstagram, and Twitter.

4 thoughts on “8 Things You Didn’t Know If You Could Compost (But Were Too Afraid To Ask)

  1. What about corn husks? I keep tomato & pepper seeds out. I figure watermelon rind is too thick, but what about cantaloupe rind? Will coffee grinds make it too acidic? Loose tea leaves should be ok?

    1. We have grown some of our best tomatoes from volunteers from the compost pile. It was particularly helpful when we were in lockdown and couldn’t get mail order plants.

  2. All these things are fine, Karen. It will help to chop them up a bit for faster decomposition, and the corn husks and cobs are slow to degenerate, but given time, they will. We like the cobs, because they kind of act like hugelkulture wood, and help absorb moisture for slow release. So if they don’t decompose completely, just bury them 8 to10 inches deep, or more.

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.