Does Potting Soil Go Bad? The Truth About This

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Last Updated on July 1, 2022

If you’ve been in a situation where you find an old bag of potting soil and you wonder if can be of any use; then you’re not alone. The potting soil may just have been sitting outside the shed for a while and it may have you wondering what to do about it. Does potting soil go bad? We will deeply look into this question in this article.

Soil that is of great quality is required to successfully grow plants whether indoor or outdoor. Potting soil ensures the plant grows in an adequate medium. It ensures our plant receives the appropriate nutrient, care, and more for healthy plant growth.

Most times, when we purchase potting soil, we may get more than what we need. So, some soil tends to remain and this makes us keep them. But what we would like to know is this: does potting soil go bad?

Does Potting Soil Go Bad? Get To Know The Truth

Does potting soil go bad? The truth of the matter is that potting soil doesn’t have a particular expiry duration. However, it can go bad if it has been kept for a long time. Also, not storing potting soil appropriately can cause it to go bad.

Does Potting Soil Go Bad

How long Can Potting Soil Be Stored?

Once you’ve opened your potting soil, it should last around 6 to 12 months. Then for potting soil that has not been opened, it can be stored for about 1 year or two years.

What Is Potting Soil Composed Of?

You should know that not every potting soil contains the same ingredients and this is because various potting soil has different purposes. There is potting soil designed specifically for indoor use and they are usually well-draining soil. Outdoors potting soil on the other hand is made to retain moisture longer.

But let’s look at the general composition of potting soil for a container garden:

  • Peat Moss: peat moss is a fibrous material that contains nutrients such as nitrogen and phosphorus for the growth of a plant.
  • Perlite: this is a volcanic glass material and this composition helps improve water retention, soil aeration, and drainage.
  • Vermiculite: this is a mineral that enhances soil water retention as well as soil aeration.
  • Bark: bark is a shredded pine bark that helps increase soil aeration and water retention.

Why Will Potting Soil Go Bad?

Usually, potting soil is inclined to go bad due to the presence of degradable ingredients they are made up of. The majority of potting soil is made up of peat moss and other organic ingredients that tend to decompose over time. Peat moss for instance is at its best for about 1 to 2 years. So, after this, peat moss can start to decompose and make the potting soil go bad.

Why Will Potting Soil Go Bad

When this soil goes bad, it usually leads to the soil losing water retention and aeration. Hence, this makes the soil inappropriate to be used on any potted plant.

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How To Tell Your Potting Soil Has Gone Bad

Most potting soil does come with expiration dates so you can simply check the expiration date. However, there are times the expiration date isn’t clear. Or the expiration date has faded out. You can still determine when your potting soil has gone bad or expired through other means.

So, you can further tell if your potting soil has gone bad by doing some checking, and here are some signs to tell you that it has gone bad:

1.    Foul Smell

Once you begin to perceive this foul, rotten egg smell, that’s an indication that your potting soil has gone bad. The reason you perceive this bad smell is mainly because of the anaerobic bacteria that grow in this old, damp, and compacted soil.

2.    Soil Compaction

When your soil is compacted, it means it feels heavy or tightly packed. This is one common issue faced with old potting soil that comprises peat moss. Peat moss is best used from around 1 to 2 years of buying it and after this duration, the soil begins to go dense as it composes of other organic materials.

3.    Mold Formation

Once you notice mold growing out of your potting soil, it has gone bad. This situation often occurs when the soil is stored inappropriately. For instance, storing potting soil that is damp in a closed bag for a long time can, especially during warm weather can cause the soil to begin to form mold.

4.    Insects Invasion

Insect invasion or infestation is another clear sign your potting soil has gone bad. Small insects such as fungus gnats thrive in soil, particularly moist soil. These insects can access your potting soil even when it’s closed through very tiny openings.

Once they access your soil, they begin to multiply by laying eggs. Inside your potting soil mix. They tend to encourage decomposition in a way that’s not healthy.

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Tips For Maintaining A Fresh Potting Soil

If you won’t be using your potting soil mix right away or you won’t be using all the soil, there are things you can do to maintain this soil mix for some period.

  • Store your unused or unopened potting soil in a dry and cool container. Then once you’ve opened the potting soil bag, store it in a dry and cool air-tight container.
  • You can revive your potting soil by mixing it in more nutrients if it has lost its nutrients before it expires.
  • Blend or mix your old soil with fresh potting mix.

Conclusion – Does Potting Soil Go Bad?

Potting soil does go bad so if you find out that your old potting mix starts to give a foul odor or it’s bringing out mold; then it’s a sign the soil has gone bad.

We have discussed some details about potting soil going bad and we hope this piece of information has enlightened you.


How do you know if potting soil is bad?

When potting soil has gone bad it will show some signs. The signs to determine your potting soil has gone bad include foul odor, mold formation, soil compaction, and insect infestation.

Is it okay to use old potting soil?

You can use old potting soil if the soil has no pests or diseases. So, ensure what you’ve used the soil to plant is totally healthy. However, sterilizing the potting soil mix is ideal for use against the next year’s planting season.

How long can you keep a bag of potting soil?

A potting soil that has not been opened can be kept and used for a duration of 1 to 2 years. However, once you have opened the potting soil, it will begin to degrade and you will have about 6 months to store it.

How do you rejuvenate old potting soil?

To rejuvenate your old potting soil, do the following: Spread and lay out the soil so you can clean the soil by taking out any debris such as rotted plant roots, weeds, and dead leaves. Then clean with water, mix the soil with a fresh mix, and add a slow release fertilizer. After doing all this, let the soil cure by storing it in a dark and dry place for about 2 weeks then you can use it.

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