Why does my compost smell bad?

my compost stinks

QUESTION: Why does my compost smell bad? I started composting a few months ago, and now it smells so bad that my neighbor has complained. -Lisa B.

ANSWER: Why your compost smells bad depends on the type of smell your compost bin is producing. If your compost heap smells like ammonia, that means the pile contains too much nitrogen-rich wet ingredients (also called “green” materials).

You can help things get back to normal by leaving the lid off your composting container on a warm, sunny day so the materials can dry out some. If your compost smells like ammonia, you should also add more carbon-rich ingredients (known as “brown” materials) to help get things back into balance.

Adding dried leaves is an easy way to get more carbon into your compost pile, but if you don’t have any dried leaves available, you can use shredded newspaper or cardboard instead.

If your compost heap smells like sulfur (like a rotten egg)  instead of smelling like ammonia, there are a few different factors that could be contributing to the smell. First of all, if you have been including meat, fish, grease, dairy products, or anything that contains these items to your compost pile, you should stop adding those materials, as they’re definitely contributing to the stench.

If you don’t use meat, fish, grease, or dairy, and your compost still smells rotten, it’s possible that your compost isn’t getting the oxygen it needs, causing a surplus of anaerobic microbes.

To resolve the issue, use a compost turner or a pitchfork to mix the heap up well, and add ingredients heavy in carbon (also called “brown” materials), as carbon-heavy materials will help soak up the extra moisture and aerate the pile to help resolve the smell. Incorporating some dried leaves into the mix is the easiest way to add some carbon to your compost, but if you don’t have access to dried leaves, newspaper or cardboard will do.