A smelly compost pile is a sign something’s wrong. Learn why compost can smells like rotten eggs or ammonia and how to fix it with these simple steps.
If you would like a refresher on the basics, see How to Compost Food Scraps.

Dealing With Stinky Compost
If your compost pile smells bad, don’t worry. It’s a common problem and usually easy to fix.
Here’s the quick summary of what you need to do:
- Add more “browns” (like shredded paper, cardboard, or dry leaves).
- Turn the pile to mix things up and get air back in.

If you’re new to composting, this guide on How to Compost Food Scraps explains what greens and browns are and why you need to add both to your bin.
Now, let’s look at why the problem happens so you can prevent it in the future.
Compost Isn’t Supposed to Stink
It’s right to assume that discarded food scraps will gradually rot and smell terrible.
But a healthy compost pile should not have a strong or unpleasant odor. If it does, something is off.
The two main warning signs are a rotten egg smell or an ammonia odor.
Why Compost Smells
Composting should be an aerobic process, meaning it needs plenty of air.
Bacteria and other microorganisms break down our waste and they need oxygen to do it properly.
If the pile gets too wet or compacted, air cannot easily move through. This is because many “green” materials like fruit peels and veggie scraps hold a lot of water, and the water can fill what would otherwise be space for air. Without enough oxygen, your compost switches from aerobic to anaerobic decomposition.
And that’s when things get stinky.
Anaerobic decomposition produces hydrogen sulfide gas: the classic rotten egg smell.
Another nasty smell you might notice is ammonia.
Ammonia is a compound made of hydrogen and nitrogen.
Nitrogen is great for compost. It’s the main food for the microbes.
But if there’s more nitrogen than they can use, the extra gets released as ammonia gas, which smells sharp and terrible.
On top of those, there are other bad-smelling gases that can be given off by anaerobic decomposition. (It can also emit methane, which doesn’t smell but is bad for the environment.)
How to Fix the Smell
Fortunately, the solution is simple.
You need to bring your compost pile back into balance.
- Add more browns.
Browns are dry, carbon-rich materials like shredded paper, cardboard, and dry leaves.
They help soak up excess moisture and reintroduce air pockets into the pile.
You might wonder why you’d want to put paper or cardboard in a compost pile when it could be recycled instead. Paper doesn’t add nutrients to compost like food scraps or yard waste do. But it absorbs moisture and helps create the right conditions for good composting, supporting the aerobic process you need for rich, healthy compost.
- Turn the pile.
Use a pitchfork, shovel, or rotate your compost tumbler to mix everything up.
This physically introduces air back into the pile and breaks up any soggy, compacted areas.
With more browns and better airflow, the bad smells should disappear quickly.
Resources
More Composting Tips
- How To Compost In The Winter (Easy Method)
- How to Compost Without Pests (Sorry, Rats!)
- Should I Use Compost Tea?
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