Compost has a scent… but what doesn’t?
Let me explain! Just like you can walk into a home and instantly know when someone is baking cookies OR if you live by someone with livestock you know when they are mucking stalls or spreading hay. Things have specific scents.
Compost, when rocking along optimally, can smell like a mix of wet dirt and wet leaves… I think anyway. Regardless, it shouldn’t make you gag. Well, when I add the 5 gallon bucket from the garage that has sat there way too long, then I hold my breath. But once it is mixed with the sawdust or other browns, the smell dissipates very quickly.
In general, if the compost stinks: stir, add browns, and make sure it’s not too wet.
There are a couple smells that often come up with people new composters, or to those that composting is old hat but different materials are being added.
- Sulfur (rotten egg) smell
- Sweet/Tangly smell
- Yeasty smell
- ammonia like smell
Sulfur smells
The rotten egg compost smell is usually because it is too wet or not being mixed often enough. Take the time to add some dry browns or spread the compost out for an afternoon to get it dried up a little before returning it to the bin/tumbler.
Mix up the compost to remove this smell if it is not a wetness problem.
Sulfur is released as a byproduct of anaerobic bacteria metabolism… it happens to the best of us. Laugh about your diy mud pot (ever been to Yellowstone National Park?), give it a mix or dry it a little and let the good ol’ composting times roll on.
There is a learning curve in how moist, but not wet, the compost needs to be in order to decompose quickly without getting the sulfur stench. If this is a constant problem, you may not have enough sunlight helping the pile stay dry? Try moving the compost area into a sunnier spot.
Sweet/Tangy smells
For anyone that has worked with school compost or has a lot of fruit in the compost, you will know or have known this tangy, tart, not pleasant smell. I thought having a lot of citrus rinds in the compost would make it smell amazing, but boy was I wrong!
To remedy this, more sawdust/wood clippings were added to the compost along with some finished compost to help balance out the bacteria load that seemed to get overwhelmed with all the citrus.
Yeasty smell
Doing as many a researcher will do, I experimented with the compost pile when it was having different issues… I read somewhere that adding beer to the compost or bakers yeast would help… Well…. it kinda did. The compost sped up, the heat was great, but the smell was like a bad day in the lab when you mess up making LB broth… or for you non-labbers, walking into a brewery making skunky beer (if that was a thing)…
Again this was remedied by adding older compost or just dirt from the garden to help balance out the microbes again and when in doubt always add a little bit of browns 🙂
Ammonia smell
To fix this, add more browns. Shocker, I know.
Ammonia smelling is indicating that there is nitrogen being released into the air, instead of being incorporated into the dirt for the plants! Recall that greens are the wet, nitrogen rich materials that are added to the compost. To make the compost cycle complete in the fasted time frame, we mix browns and greens at a nice ratio… ammonia smell means that ratio is green heavy and needs some browns. No biggie.
To avoid having to trouble shoot every smell in the compost, when in doubt do 3 things:
- Make sure the compost isn’t dripping wet and is just moist
- Stir it
- Add browns ( I like sawdust or small wood chips/mulch)