How to Store Worm Castings Properly & How Long Before They go Bad?

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Knowing how to store worm castings is easy to learn, and it’s really worthwhile to create your own stock of castings.

With a little planning, you can turn any non-airtight container (or even an airtight container with the lid slightly ajar or with holes drilled in the lid) into a usable supply throughout the year.

By having your worm compost instantly available when needed, you can save time and money.

Not only is worm compost the best food for your plants, but it’s also a great way of dealing with any organic matter scraps that you have. But how do you store worm castings? 

When storing worm castings, you will need an adequate container for airflow and moisture content, a space with the right temperature, and an area that you can frequently reach in order to keep your worm compost nice and healthy.

It is essential to understand that worm compost contains living organisms, including anaerobic bacteria, which need a specific environment to survive.

Can Worm Castings Go Bad?

No, worm castings cannot go bad. They can dry up if not maintained during storage or may freeze in winter. Drying out or freezing may kill some of the living organisms.

Can Worm Castings Go Bad?

This means the worm casting supply may not be as successful to fertilise your plants.

That is why storing worm castings properly is essential.

Thankfully, there are a few things that you can do in order to ensure that your worm compost remains as perfect as possible. 

Where to Store Worm Castings?

As there are living organisms in your supply of worm compost, they require an environment similar to that of your healthy plant soil.

In order to have the perfect storage for your compost, you need an adequate amount of two things: air and moisture.

A Plastic bucket is ideal for retaining moisture.

If you choose to use a bucket, then you will need a lid to protect the compost from the elements and prevent it from drying out.

Where to Store Worm Castings?

You will also need to ensure the castings have an air supply.

To facilitate this, you will need to drill several holes towards the top of the container.

However, do not leave the lid off instead of creating holes, as too much water will spoil your compost.

On the other hand, you will need to ensure that the castings remain moist.

You will need to add moisture. You can do this by using worm bedding, as you would in the worm bin, then add water with a spray bottle. 

You can use wet newspaper, peat moss, shredded paper, etc.

Place the lid on top, and then write the date on the side of the container.

By dating them, you will know the order in which you should use the compost. 

How Long Can I Store Worm Castings?

It takes approximately 3 to 6 months for worm castings to be in optimum condition for use. This depends on when and where they are stored.

Worm castings have a shelf life of up to a year.

How Long Can I Store Worm Castings?

However, in order for them to last that long, you need to remember to store them properly in a bucket (and drill holes where needed), seal the lid, and keep it in a safe storage area. 

How Do You Store Worm Castings Over Winter?

Ideally, you should store worm castings in your labelled bucket in a shed, greenhouse or even a garage.

This will make it easier for you to maintain the moisture levels, topping up with fresh bedding material every few weeks. 

Worm castings can be stored outside and can withstand freezing just fine.

If it snows, you may have more work to do, checking moisture and replenishing it. It can be awkward to remove/replace the cover if it has frozen, too.

In extremely cold weather, a plastic bucket can become brittle and crack.

storing worm castings properly

Can You Freeze Worm Castings?

Worm castings that have been overexposed to water or ice will still have value. In the same topsoil in a garden recovers, worm castings do too.

Some gardeners deliberately place worm castings on the surface of their garden prior to the onset of winter.

This bolsters up some nutrients by trickling organic nutrients into the soil with rain, melting snow or ice.

Can You Freeze Worm Castings?

While some microorganisms may die or become dormant, they can still be a welcome treat for winter or early spring crops.

Topsoil freezes in winter and many plants survive. Sometimes leaves are lost, but roots may survive. Worm castings behave the same way as the in the garden soil.

Should You Dry Worm Castings?

No, you should not deliberately dry worm castings. The purpose of placing moist paper at the top of containers is to ensure that the living organisms in your containers, do not dry up.

Whether stored inside or outdoors, you are advised to check that your worm castings remain moist and top up moisture levels accordingly. 


Worm castings are ideal for a multitude of reasons. For one thing, storing castings is cheap and easy to do. 

Conveniently to hand when required, your homemade supply of fertiliser is PH neutral. No unpleasant chemicals are added.

This means worm castings are ideal for use if children or pets are likely to be near the land and are completely organic and nutrient-rich, making them ideal for feeding your own garden.

Nutrients include Magnesium, Nitrates, calcium, potassium and Phosphorous. Worms do more for your garden than you might imagine.

In the ground, the microorganisms would not be subjected to chlorinated water; therefore, it would be a great idea to use rainwater to moisten the fertilizer.

If you do not have a water bottle, simply put a container of tap water outdoors for a minimum of 24 hours and the chlorine will have disappeared.

Worm composting is an excellent way of fielding your vegetation to suit the growing seasons. Overwintering castings can kick start new crops with the best nutrients.

Conversely, after a demanding growing season in summer, you can replenish valuable nutrients in the soil using your own fertilizer.

If you should have any spare worm poop from your vermicompost, neighboring gardeners may be grateful for donations.

Storing the produce adequately will also greatly reduce waste. Simply reuse that same bucket every time you need more vermicompost to be harvested.