Carbon cap & store

Capping your compost with carbon

There is a little trick you can do every time you add ingredients to your compost pile that can really improve how well it works. Cap your compost with carbon.

Now, this might sound like something from the Kyoto Protocol that governments couldn’t get international agreement on, but it is much simpler than that.

Every time you build another layer of your compost pile, finish your composting session by covering your pile with a generous capping of carbon rich materials.

Joel digging straw
into his compost.

“Straw is the king of carbon capping materials. It is rich in carbon, but has a texture that makes it very good to layer over a pile.”

 This carbon capping is our last line of defense against bad gasses and bad odours being emitted from our compost.

Methane and nitrous oxide are the dangerous gasses from a climate perspective, but ammonia is also a form of nitrogen leaving our pile as a gas. We don’t want to lose any of these from our compost if we can help it, our compost and the climate are better off if we retain them.

By covering our pile with a carbon rich capping we create a biological filter that, with microbial help, can catch and convert these gasses into useful food for our compost pile, we lose less and get to keep more.

Straw is the king of carbon capping materials. It is rich in carbon, but has a texture that makes it very good to layer over a pile, it also has insulative qualities, in winter - trapping heat, and in summer - protecting from the hot sun.

Carbon capping is not a substitute for good composting practice. We still need to get a balance of carbon and nitrogen rich materials, maintain a good moisture content in the pile (wet, but not dripping) and blend with enough coarse material to keep oxygen getting into the pile and carbon dioxide getting out, but fine enough to keep everything in contact and connected.

Even very experienced composters don’t get the perfect balance every time in their compost piles, so capping with a good cover of carbon can help when things are not quite perfect down in our pile.

Next week we’ll have a look at tips for cool composting.

AUTHOR: Joel Meadows

Joel Meadows works with *Yes In My Back Yard, (YIMBY), a community-scale composting initiative in Castlemaine and surrounds. Send questions or comments to hello@yimbycompost.com

This story was first published in Midland Express on 15/08/2023. Read it here