Does Compost Go Bad?

Nutrient-rich compost frequently sits unused for months. Can it go bad?

When I first started composting, I made more than I was able to use. It sat around in my yard and started attracting flies. One summer day, I wanted to use it to improve the soil, but I had no idea if the compost had gone bad.

Can you use old compost and is there anything you should be doing to prevent it from going bad?

What Happens When It Is Old?

Compost really cannot go bad. 

It is best to use your compost within three to four months after it is done. However, it can still be used even after that.

Over time, the nutrients in the compost break down. This process takes a long time, so you probably won’t have to worry too much about it. As long as you don’t store it for a few years, there won’t be any difference.

How Do I Store It Properly?

If you have a place outside where you can store this soil nourishment, you should do that. A tarp or a container with a lid is the best way to keep it safe from the rain.

If you need to keep your compost inside, look for a place that is dry. Then, consider the temperature. 

When it’s cold, it takes longer for things to break down. So, storing your compost in a cool place keeps the evaporation rate the same and won’t affect the decomposition. If you want to give the break-down process a little boost, store it in a warm place and let the temperature speed up the process.

Make sure your container is in a safe spot, like on the ground or away from the edge of a shelf. Make sure nothing can fall on it or knock it over.

Also, make sure small children and pets can’t get to the container. As a general rule, compost isn’t bad for people or animals, but there are bacteria in it that can cause a problem if ingested. If the storage container itself is heavy, it could hurt someone if it falls over.

A locked shed or closet would be good places for storage.

A person checking the a home made soil compost in the large container

Why Does My Compost Smell Bad?

A well-balanced compost pile should not emit any bad smells. If the pile doesn’t smell like dirt, then something is likely wrong. It means that the temperature is not high enough and the organic material in the pile is not breaking down properly.

A bad smell can also mean that there are too many greens (nitrogen material), not enough air, or too much moisture. If the compost isn’t mixed well, it can also emit bad odors.

Why Are There Bugs Bugs?

Bugs are almost certain to show up in the “cold” composting that most people do in their backyards. For the most part, you can and should learn to live with a healthy number of bugs. It really is just part of passive composting.

Bugs can support decomposition, so if you can get over the “ick” factor, you will see the benefits. Most of the bugs are not dangerous to people. Just keep an eye out for poisonous spiders and bees, if you are allergic.

A hand holding some soil from a house compost container

Can You Use It If It Has Mold?

If you see mold in your compost, you should prepare to give it a nice turn to improve the air flow. The mold is unlikely to hurt you if you happen to touch it while turning over the materials. However, try not to ingest any of the mold. And if you are sensitive to mold spores, you should wear a mask while you work. 

Once the materials in the pile have broken down, the mold should die off, making it safe to handle and use. 

Why Is My Compost Slimy?

Too much water can prevent materials from breaking down properly, turning your compost pile into a slimy mess. All that extra water will do no good, and it can even hurt the pile in the long run. 

Try letting your compost air out as much as possible, turn it, and perhaps cover it to shelter it from too much rain.

Jeffrey Douglas
Jeffrey Douglas own a landscaping company and has been in the business for over 20 years. He loves all things related to lawns or gardens and believes that proper maintenance is the key to preventing problems in the first place.
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