There is a skill in adding the right mix of “brown stuff” and “green stuff” to your compost. Too much green and your pile will start to smell. Too much brown and your compost will move slower than a herd of turtles stampeding through peanut butter.
Green or Brown?
So, how do you know whether something is “green” or “brown”? Brown ingredients are high in carbon and include materials like leaves, straw, and sawdust. For a harmoniously balanced pile, brown should make up about 2/3 of what you compost.
I’ve listed brown stuff starting with the highest carbon content materials. The number afterward is the approximate carbon to nitrogen ratio, which you can ignore unless you are a numbers geek like me. Just know, bigger numbers = more carbon.
“Brown” or Carbon-Rich Materials (C:N Ratio)
Pine Needles (100:1)
Green, or nitrogen-rich materials, speed up the composting process and add important nutrients. Greens are an important addition to your browns, like the yin to your yang, the cream to your coffee, the Simon to your Garfunkel…you get the idea.
Anything you add to your pile will technically have more carbon than nitrogen (carbon is the basis of all life on Earth in case you missed that day in science class). However, some items, like grass and manure, have relatively high nitrogen content. I’ve listed these nitrogen-rich items starting with those highest in nitrogen content.
“Green” or Nitrogen-Rich Materials (C:N Ratio)
Fruit and Veggie Scraps (15:1)
Coffee Grounds (20:1)
Garden Waste (30:1)
At the most basic level, you want 2/3 stuff from the brown list and 1/3 stuff from the green list. If your pile starts to smell, you probably need to pull from the brown list. If you’ve got the “stampeding turtles” pile, grab more from the green list.
If the ratio numbers above made your heart start pounding with excitement, you can learn to use those numbers here. A world of ratios, sums, and other math geeky fun await.
It doesn’t have to be that complicated, though. Everything will break down eventually, you'll just speed up the process and avoid a smelly pile if you pay attention to your browns and greens.
After a while you gain an intuitive “feel” for the right balance. Don’t worry, I’m not going to suggest you “become one” with your compost bin. Just use common sense and eventually you’ll find a Zen-like balance. At least for your compost bin.