Wasted Food Dude–Backyard Methane??

Here’s the latest installment of my food waste advice column, Dear Wasted Food Dude, which also runs on BioCycle‘s site and their e-bulletin, BioCycle Food Recycling News. 

Related: send questions! All food-waste-related queries are welcome–big or small, true or false, named or anonymous. Send stuff to wastedfood {at} gmail or @wastedfood. I bet we could all use a diversion from politics…

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Dear Wasted Food Dude,
Does a backyard composter produce methane? If so, should I / can I do something to reduce it?
— Kai R., Arlington, VA

Hi Kai,
The shortest answer is: yes. Yes to all of your questions!

While it doesn’t have to, backyard composting usually does produce some methane. The uber-simple version is that when your food scraps don’t have access to oxygen, methane is created.  Commercial composting operations ensure that their materials have steady exposure to oxygen, whereas backyard composting requires us to make that happen. And we the people are not infallible, sadly.

How much methane does backyard composting create? Study results aren’t exactly piling up (compost joke), but in general, “Home composting can be a significant source of methane,” explained Sally Brown, soil scientist and Research Associate Professor at the University of Washington. “Home composters are less likely than municipal or regulated facilities to monitor aeration.”

Given that unfortunate reality, you have two choices: 1) dedicate yourself to turning your compost pile to ensure aeration; or 2) leave it up to the pros! Almost all commercial composters have that aeration thing figured out. They’ll also be able to compost meat and dairy scraps because their compost pile gets hot enough to process those. Then again, you’ll save money and carbon emissions (unless they’re collecting by bike!) by composting in your backyard. Decisions, decisions.

You also asked if you should do something about composting’s methane output. Hang on a sec — let me put on my Ethicist Dude hat. Doesn’t really fit, but here goes: Given methane’s harmful impact as a greenhouse gas and the scary reality on climate change, you really should. Methane is about 23 times more potent at trapping heat in our environment than carbon dioxide.

And part of the reason you really should try to limit composting methane is because it’s not a huge deal. Basically, you make sure you have about twice as much brown (leaves and other dry materials) in your pile to green (food scraps). From there, you basically just stir it around every so often. Just a hint of effort needed.

Still, some readers might hear that composting could create methane and opt out altogether. Backyard composting — with or without methane emissions — is still miles better than not composting. All of the food sent to landfill creates methane emissions (because it decomposes without air). Opting out is like choosing an SUV over a hybrid car because the latter isn’t an electric car. If the perfect is the enemy of the good, the bad is a much bigger foe!

Finally, it’s worth noting that processing your own excess has several intrinsic benefits. Composting forces you to notice the waste you’re creating, prompting behavior changes. It creates a personal, local supply of useful soil amendment. And there’s something to be said for self-reliance. That concept, like composting itself, is inherently virtuous.

Just remember, compost happens. But it happens better with a little effort.

Keep turning that pile,
WFD