Sustainable Missoula: Simple mysteries of composting answered

For many, composting can be a mysterious world of “do” and “don’ts.” Even though it is easy to let the details of the process overshadow the immense benefits, the principles of composting are quite simple and rather forgiving. 

To understand the composting process, I like to lean on the idea of “values.” By nature, the food we grow and eat contains abundant value; structurally and nutritionally. Even though we might deem our yard waste and kitchen scraps of little value to us, intrinsically, they are still chalked full of potential purpose. Composting is the act of fostering the decomposition of all organic materials which includes your pizza boxes, coffee filters, grass clippings, and carrot tops.

Through this process, those organic values are transferred into what some call “black gold” that can be used to grow more nutritious food, continuing this valuable cycle.

Composting is a simple, yet seemingly complicated act that Mother Nature accomplishes effortlessly. As the director and founder of a composting organization, I find myself in a lot of compost-related conversations. From family to friends, it seems that almost everyone has a question about the mysterious world of composting. In hopes to help all of you on your journey, I have compiled a list of the most common composting questions I receive.

1. Why isn’t my compost pile breaking down? 

While there are a lot of answers to this question, the main issue is balance. Successful composting relies on a healthy balance of materials, water, and airflow. The most common issue for stagnant piles is a lack of water. If the activity in our compost pile dramatically slows down in late summer and fall, make sure your compost is soaked clear though. The moisture consistency of compost should be that of a wrung-out sponge. 

2. What heats up a compost pile? 

Organic materials will slowly break down in a “cold” compost pile but to churn finished compost out in time for garden season, thermophilic “hot” composting is needed. Commonly mistaken for the sun’s heat, compost piles are primarily heated by replicating bacteria. These microorganisms require the valuable nutrients of nitrogen, phosphorus, potassium, oxygen and water to live, grow and reproduce.

These nutrients are supplied through the materials you add to the pile. To speed up the process, you can give the bacteria in our compost pile an extra boost. Adding previously finished bacteria-rich compost, compost tea, starter food, or even sugar water can help feed the bacteria in your compost pile. 

3. What about compostable containers? Compostable vs. Biodegradable 

The market of compostable and biodegradable containers is constantly growing. You might have seen plastic-looking cups, cutlery, garbage bags, and even cell phone cases that claim to break  down. Often used interchangeably, “compostable” and  “biodegradable” are very different classifications and require different conditions to break down.

Biodegradable refers to materials that can be broken down without oxygen in a “reasonable” time, often requiring special enzymes or microorganisms. Simply stating, most “biodegradable plastics” are still plastic! On the other hand, compostable packing is most often manufactured using plant-based materials, allowing them to break down in a traditional or industrial composting facility.

While not all compostable materials are certified, you can look for the BPI Compostable label on many packaging. While it is easy to compost paper containers at home, compostable “plastics” require temperatures between 120 and 140 degrees, which causes materials to warp and quicken the process which can take 90-200 days. 

4. Is there a simple way to remember green/brown ratios? 

If you have learned about at-home composting, you might have heard the terms “green” and “brown” materials. “Green” refers to nitrogen-rich materials like food scraps, fresh grass cutting, and coffee grounds. “Brown” refers to carbon-rich materials like dry leaves, shredded paper, and wood chips. A compost ratio is the balance between these two ingredients. Since all organic materials contain carbon, getting into ratios can get complicated.

To simplify things, I focus on ratios by volume, not carbon. Two parts “brown” materials to one part “green” materials usually provides a solid ratio for the home composter - 2:1. That could look like 2 handfuls of leaves to a small bowl of food scraps each time you add to your compost bin. 

Even though there are numerous topics to cover about composting, I hope these answered a few questions. When in doubt, remember that anything that once came from the Earth can and wants to return to it. And don’t hesitate to ask, “Is this compostable?” 

Caitlyn Lewis, Soil Cycle executive director 

Sustainability Happenings

Here we offer ideas about sustainable ways to stay involved in our community. For more, consider signing up for Climate Smart’s eNewsletter. And sign up for the Home ReSource eNews via their homepage.

Missoula’s WINTER Farmers Market continues in Southgate Mall, Saturdays 9am to 2pm. Until April 23. Also on Wednesdays 4:30- 7pm until Dec 22.

Now to Feb 27 — Ski for Stewardship– Benefit for 5 Valleys Land Trust. Info here 

Feb 18 to March 3.  Big Sky Documentary Film Festival. Many films have environmental themes. Festival is in-person in Missoula Feb 18 to 27 and online Feb 21 to March 3.

Feb 18. New Member Welcome Calls -, 12-1pm; March 4, 9-10am (virtual). Meet other parents and caregivers in Montana (and beyond) who have joined in some kind of climate action, discuss your interests and concerns in a supportive context, and learn about volunteer opportunities. 

Feb 19. Beginner Bird Walk at Metcalfe Wildlife Refuge in Bitterroot Valley, led by 5 Valleys Audubon. 10 am – 1 pm.  Info on their calendar. 

Feb 22. UM’s weekly webinar series on Our Environment Matters continues. 6 UM professors explore human impact on environmental sustainability. 7pm. Tonight: Invasive Species in Flathead Lake. Info/register here.   

March 3. Climate Conversations Skills Workshop - (virtual). 12-1pm Learn and practice skills to have effective climate conversations with our family, friends, and colleagues.

March 7. Zero Waste Schools Film Screening & Panel Discussion -, 5:30-6:45pm (virtual). Watch & discuss the film,  Microplastic Madness , as well as what is happening on the Zero
Waste and plastics reduction scene in Missoula, with a special focus on the Zero Waste Pilot program launching in MCPS this spring.

March 12. (Sat)– Fixit Clinic Missoula at the University of Montana UC. Come learn how to repair your beloved broken items and torn clothing! 12 pm – 3 pm. Register Here.  

Materials donations to Home Resource keep the wheels of reuse spinning in our community; and remember that everything you need to know about what to do with your unwanted stuff is at www.zerobyfiftymissoula.com.

Find more local activities and events at Missoulaevents.net and on Montana Environmental Information Center’s Conservation Calendar. And you too can help organize events – here’s the 2021 Calendar of Environmental Awareness Days – month by month breakdown of world day campaigns.