Does Vermicompost Ever Expire? A Simple Answer

Vermicompost is an excellent organic fertilizer because it’s rich in all the essential nutrients. However, it takes time to make it, so you’ll need to make a plan. It’s also good to know how long it lasts (and whether or not it expires) if you’re interested in making vermicompost at home.

Vermicompost expires within a few years, but the quality can decrease within a year if it’s not stored in the best conditions. For vermicompost to last as long as possible, it must be at the right temperature and have adequate moisture. Also, fresh vermicompost shouldn’t have a foul odor.

Understanding how long vermicompost lasts is essential, and this article will discuss that in detail. It will also discuss how to ensure your vermicompost lasts as long as possible and the best time to harvest the worm compost.

How Long Does Vermicompost Last? 

Vermicompost lasts for at least six months, but it can often last longer than this under the right conditions. One of the essential things for vermicompost to last a long time is moisture. Without enough water, the vermicompost will dry out and won’t be as effective in the soil.

If you create a vermicompost bin, you can harvest the worm castings in as little as three months. However, some people might prefer to wait longer. Once you’ve reached the three-month mark, you can look at the vermicompost and decide whether or not you want to give it more time.

Technically, a vermicompost bin can last for at least a year (and even longer) if you harvest worm castings regularly and place the remaining worms back into the container to begin the process again. 

According to the University of California, it’s likely that some worms will remain in your harvested compost, but luckily, they won’t survive long in the soil. So, although you should try removing as many worms as possible from the compost, having a few strays won’t harm the soil once you add them to the ground.

Place all the worms you manage to separate from the harvested compost back into the vermicompost bin. From there, you can add more organic matter and repeat the process many times. This way, your vermicompost can last a very long time!

How To Ensure Vermicompost Lasts As Long as Possible

It’s vital that your vermicompost be in the conditions it needs to thrive and survive. Once the temperature and moisture levels are correct, you can expect it to last at least a year (possibly even longer.)

However, the exact requirements will vary depending on what stage you’re at (i.e., if it’s before or after the harvesting stage). 

Below, I’ll discuss how to ensure your vermicompost lasts as long as possible before and after harvesting.

Before Harvesting

Before you harvest your worm castings, you need to make sure the worms in the vermicompost stay alive so that they can continue their job. To ensure this is the case, you must:

  • Keep the temperature stable.
  • Ensure there is enough moisture.
  • Keep adding organic matter.
  • Ensure there is enough airflow.

The worms won’t survive without these things, meaning they won’t release castings (manure). As a result, you won’t be able to harvest the castings, which is the whole point of vermicompost! Let’s look at each point in more detail below:

Keep the Temperature Stable

Keeping the temperature stable is essential if you want the worms to survive and last a long time. The ideal temperature for a vermicompost bin is between 59 and 77 °F (15 – 25 °C). You can use insulation (blue board) and straw to maintain an appropriate temperature if you have any difficulties. 

Ensure There Is Enough Moisture

Vermicompost bins need moisture, so you should add water as necessary to keep things moving healthily. There are no guidelines on when you should add water to the container–generally, once every week or two is good. 

But if you live in a dry environment, you’ll need to add water more frequently. If you apply too much water, you can add extra shredded paper to soak it up.

Keep Adding Organic Matter

To keep the worms thriving and producing valuable castings for many months (and in some cases, years), you must ensure they’re receiving enough organic matter. However, avoid feeding them too much organic matter, as this can cause spoilage and bad smells in the bin.

If the worms in your vermicompost bin are healthy, expect them to eat half their weight in food every day. And keep in mind that overfeeding can be very bad, but underfeeding isn’t as detrimental. So if you think you’re giving the worms too much food, stop adding food so frequently.

Some of the best things to feed worms in a vermicompost bin include:

  • Squash
  • Watermelon
  • Cantaloupe
  • Teabags
  • Carrots

Ensure There Is Enough Airflow

Good airflow is also essential for vermicompost bins. The best thing to do is drill holes around the container. Although it’s OK to drill holes in the lid, preparing some on other sides (including the bottom if placing the bin in a raised position) is also good. 

You might be thinking–why can’t I keep the lid off if the vermicompost needs airflow? Unfortunately, you’ll need to block the light out with a cover, so you’ll need to keep it on. Leave a small gap for extra airflow.

Ensuring there is adequate airflow will help the vermicompost last a long time.

After Harvesting

Now that I’ve discussed how to care for vermicompost before harvesting, I want to discuss how to make it last after harvesting. When you harvest vermicompost, the results are known as worm castings. 

As I mentioned before, you can harvest worm castings in as little as three months. Once you harvest them, you can use them immediately or store them for later use. 

If you want to store the castings away after harvesting, below are the most important things to note:

Keep the Environment Moist

Like the vermicompost bin, you also want to keep your harvested worm castings moist if you want them to last a long time. If you cared for the vermicompost bin and gave it enough moisture, the castings should be adequately wet when harvested. 

To keep them this way during storage, place the castings in a container that retains moisture. However, you don’t want to use a completely airtight container–although retaining moisture is essential, oxygen is also necessary.

Store in an Appropriate Container

Here are some containers you should consider when storing your harvested worm castings:

  • Sandbag. A sandbag contains many holes, so it allows for adequate airflow. However, be aware that your harvested worm castings may dry out in a sandbag, so it’s not the best for long-term storage.
  • Plastic bucket with holes. When you make vermicompost, the best container to use is a plastic bucket. A plastic bucket is also a good choice for the worm castings you harvest from your vermicompost because you can make your own holes and retain moisture.

If you store the harvested castings in an appropriate container, they can last for over a year!

When Should You Harvest Vermicompost?

You should harvest vermicompost after three months. At this point, there should be enough worm castings to harvest. Once you’ve gathered them, you can place the worms back in the bin and repeat the process.

If you have a large vermicompost bin and plan on harvesting a large batch of worm castings at once, you may want to wait longer than three months. Sometimes, it’s best to wait around six months for a significant amount of castings to develop.

If you leave the vermicompost for longer than six months, it shouldn’t expire. But to keep it in good condition, you’ll need to maintain it by adding organic matter frequently.

Final Thoughts

Vermicompost will generally expire or become less effective within a few years. However, it won’t last long if you don’t give it the necessary conditions like adequate moisture and airflow.

You can harvest vermicompost from three months onward because there should be enough castings at this point. The more you want to gather, the longer you’ll need to wait.

After harvesting, you can store the worm castings in a container for a year or more under the right conditions. 

Alexander Picot

Alexander Picot is the principal creator of, a website dedicated to gardening tips. Inspired by his mother’s love of gardening, Alex has a passion for taking care of plants and turning backyards into feel-good places and loves to share his experience with the rest of the world.

Recent Posts