How to store potting mix

Planning on storing potting mix for the winter?

Regardless of whether you store your potting mix inside or outside, it is important to protect it.

This is a simple guide on how to store your potting soil correctly. By following the steps below, your potting mix will remain uncontaminated and viable for next season.

Preparing your potting mix for storage

First, check for pests, such as fungus gnats and their larvae, that may have found a home in the soil.

Next, let the mix dry out completely. This may require you to leave it in the sun for several days.

Turn it over with a garden fork or shovel so that all sides get exposed to air and sunlight.

You don’t want to store wet or potting damp mix—it should be dry so that it doesn’t grow mould or mildew during storage.

Storing potting mix outside

For outdoor storage, you’ll want either plastic containers or heavy duty plastic bags.

The bag your potting mix came in is neither waterproof not durable enough to store potting mix long term.

Use airtight containers to store potting mix. The airtight containers should be opaque, waterproof, strong and durable, pest-proof, and large enough to hold all of the potting mix.

Clean any container thoroughly before using for storage. This can be done with a mixture of bleach and water.

Let the containers completely dry before adding the soil.

If you don’t have a shed or garage, you can store potting soil outdoors under a shade cloth.

A shade cloth protects the soil from direct rainfall and helps keep it dry. It also stops the sun from breaking down the nutrients in the mix.

Storing potting mix indoors

To store potting mix indoors, you can use a container of your choice, as long as it’s clean, dry and sealable.

Some good options are buckets or plastic bins.

Keep them in a cool, dark place like a closet or basement. Avoid areas with high humidity.

Keep it cool, dark and dry

Potting mix can be kept in a cool, dark, and dry room (avoid direct sunlight) away from heat, cold, and moisture.

Do not store it where it may get wet or damp, as this could result in mould or fungus growth.

If you must keep the potting mix indoors during winter months when temperatures are near freezing outside, put it on a shelf rather than leaving it on the floor.

Can old potting soil be reused?

It’s generally fine to reuse potting soil if whatever you were growing in it was healthy. If you noticed pests or diseases on your plants, it’s probably best to not reuse the potting mix. Also, new potting mix will usually perform better. If you want to reuse old potting mix, rejuvenate it with some fresh potting mix and some soil-revitalising product.