A small compost pile is hidden behind a gray shed on Gary Street in Columbia. What looks like a pile of twigs and leaves breaks down the food waste of four households.
One of those houses belongs to the operations director for the Columbia Center of Urban Agriculture, Carrie Hargrove.
“I may not be getting a lot of compost out of it, but it’s the right thing to do,” Hargrove says.
Every week, Hargrove and her neighbors dump nitrogen-rich food scraps they call “greens” into the pile behind the shed. Today, she pours out bits of tomato and other scraps from the greens bucket.
“The greens kind of smell when they break down, so you need to cover them with browns,” Hargrove says.
“Browns” can be any dried dead plant matter, like dried leaves, egg shells or paper, which are filled with carbon. They are used to cover the greens in a compost pile. Generally, the pile should have twice as many browns as greens, says Jody Cook, director of compost education for the city of Columbia. “The rule of thumb is more carbons.”
Turning or mixing the pile with a pitchfork speeds up the composting process because it circulates oxygen to the bacteria that is breaking down food waste, Hargrove says.
The pile also needs moisture. Cook says if the pile is in direct sunlight during the summer, it might need to be watered. “It should be moist like a wrung-out sponge.”
When the compost is finished, “it literally smells like a delicious, earthy smell,” she says.
According to Cook, the difference between composting and rotting food is management. Compost piles need the right ratio of carbon, nitrogen, water and air, which is not available in a landfill.
Organic waste accounts for 32% of municipal solid waste in Missouri according to the 2018 Statewide Waste Composition Study. A local composition study completed in 2017 showed about 43% of material going to the landfill from residents was compostable paper, yard and food waste.
“It's really a good idea to keep those food scraps out of the landfill because they are going to break down much better outside of the landfill,” Hargrove says.
After five years of composting, Cook is able to limit her monthly trash output to about a third of a trash bag. “I’m not a big consumer of things I don’t need,” Cook says.
Cook became more conscious of the food she was buying and throwing away when she started composting.
“It can lead to a big behavior change,” Cook says.
Cook says she doesn’t buy a lot of food packaging that isn’t recyclable because she buys her groceries from Whole Foods, which does not sell products in single-serve plastics. “It has made me more mindful. I buy only what I need and I cook it,” Cook says.
When she does have food scraps, she peels back a layer of Amazon packaging paper and places the scraps for her red wiggler worms to get to work. Red wiggler worms are a special species of earthworm that, unlike regular earthworms, have a special digestive tract designed to feed on decaying organic material.
This makes them perfect to vermicompost indoors, which is different from outdoor composting where bugs, bacteria and fungi break down food. One pound of red wiggler worms can compost up to 1 pound of food waste every week.
People can get red wiggler worms from a vermicomposter or order them online.
“I used to kind of worry about them, but I have learned less attention is better,” Cook says.
If you are interested in composting with worms, Cook recommends reusing household items instead of buying something new. She says most people start with a plastic bin and cut holes around the top edge.
After all the materials are gathered, she places the worms and about a cup of soil inside the bin. Cook says the worms also need browns in the form of bedding or shredded paper.
“Shredded packing paper that comes in all those packages tends to be my favorite,” Cook says.
The worms vermicompost some of the food scraps from Cook and her co-workers. The rest of the food waste is composted at the Capen Park Compost Demonstration Site, which Cook operates for the city.
“Vermicompost is actually a richer compost than the compost in your backyard,” Cook says.
Cook’s bin sits under a table at her office. “Some people even make furniture like benches or coffee tables out of their vermicompost bin,” she says.
Composting food waste is merely one of many ways people can start living a more sustainable lifestyle, Cook says.
“It is so easy and something each and every one of us can do to reduce our food waste.”