Composting Tip: Keeping the Carbon/Nitrogen Balance

Last weekend, we came home with an exciting new purchase. Since our open-air compost bin was full, and it wasn't decomposing as quickly as we hoped, we decided to spring for a compost tumbler. And wouldn't you know, we found one on sale! Having learned a couple of things with our open-air compost heap, we started this one out armed with more composting know-how and the determination to do things a little differently. Here's one of the most important tips we've learned. While we're waiting for our open-air bin to decompose on its own, sans-turning, we're making sure we do things right in our tumbler. Everything is getting cut into small pieces before going into the bin, and we're well aware of the "brown and green" composting adage. But just why are browns and greens so important?

It has to do with keeping a well-regulated carbon/nitrogen balance. If a compost heap leans too far to the nitrogen side, the extra nitrogen will actually convert to ammonia gas (making it smell gross). A heap that's got too much carbon won't decompose as quickly (obviously one of our open-air problems, along with not keeping our open-air heap wet enough).

According to Organic Gardening magazine, the ideal compost heap has a 30:1 carbon/nitrogen ratio, more easily digest as two parts "browns" to one part "greens" (we know that's more like 2:1 but stick with us). Which is helpful, but... what's carbon and what's nitrogen?

Here are a few easy tips to keep your carbon/nitrogen ratio just right.

Nitrogen (think green): table scraps (non-dairy and non-meat), fruit and vegetable scraps, coffee grounds, tea leaves, grass trimmings, various other green clippings (i.e., weeds, flowers, and seaweed).

Carbon (think brown): dried leaves, cardboard, wood chips, straw, corn cobs, sawdust, dryer lint.

Remember, your compost should always be slightly wet—about as damp as a wrung-out sponge, is what most gardening sources tell us.

Have any other good composting tips? Do share!

Related posts:
All About Composting: Hot Tips, Best Bins, and WORMS!
Creative Kitchen Compost Keepers

(Image: Flickr member Joi, licensed under Creative Commons.)

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