Compost Sniff Test

What’s that smell? Compost shouldn’t have an assaulting aroma as you approach your pile, but compost is like baking- you can give it a sniff once in a while to determine how well your pile is doing. So what smells are good and what smells should you look out for?

Mmm, that’s good compost:

If your compost smells slightly sweet and earthy, your compost is thriving and on the right track. Think: wet leaves and a recently dug out flowerbed. Where can I buy a candle like that? Some good compost might have a little bit of a mulch-y smell to it if it’s a little stronger, but that’s not a bad thing!

Hmmm, something smells iffy:

If your compost is starting to smell a little like eggs, or has a sour smell, it probably is not getting enough oxygen. But don’t fret yet! You can fix that. Give your compost a good turn, and top it off with some new “browns” to cover any lingering odors that could have come from it. After mixing, it should be back to normal in no time.

Uh oh, that can’t be right:

If your compost smells like trash, you know, trash that has been sitting in the sun too long, and if it can be smelled from any distance away, you need to adjust your recipe. First, ensure you aren’t throwing meat or dairy into your compost bin. These can be sources of some of the strongest bad smells, and can attract vectors, which you don’t want scurrying around your pile. If you haven’t been using meat or dairy products, but your compost still smells like an old trash can, you need to adjust your ratios. You probably have too many food scraps, and not enough brown materials. Add more browns, and if it’s bad, add lots more. And guess what- It's a great time to stock up on browns with all the falling leaves outside! Give your compost pile a good turn to ensure the compost isn’t going anaerobic, and then add even more browns to top it off, this should help rectify odor and your compost can start smelling earthy and sweet soon enough.

In general, your compost shouldn’t have a strong smell at all. If you add the right mix and turn regularly, you will be just fine. What other indicators do you use to check in on your pile?

Compost Blogger: Sam Goubeaux