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How to Get Rid of Potting Soil Smell? (Causes & What to Do)

We want our home to feel nice and clean, but a musty smell from our houseplant’s soil can ruin the entire experience. Everyone in the hobby goes through this where they face the problem of foul odor in their potting soil. But what causes a foul smell in the potting soil, and how can we get rid of it? Let’s find out!

Lack of aeration, poor drainage, and overwatering is the root cause of foul odor in potting soil. Inappropriately decomposed organic matter can also lead to a bad smell in the potting mix. Let the soil dry out, then blend 1/3 cup of activated charcoal with four quarts of potting mix to minimize the foul smell.

In this guide, we will look at certain points that describe the reason behind the potting soil smell and how we can prevent it. Generally, the root cause is overwatering the plants. However, is that the only problem?

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What does bad soil smell like?

The fresh soil has an earthy smell, and it feels nice to be around it. That smell of soil which we get after the rain, isn’t that one always needed?

The soil that goes bad gives an unpleasant odor. It might smell like rotten eggs and smell as if it has traces of ammonia and sulfur.

The soil smells bad even because of a lack of oxygen and if the soil is overwatered. Bad drainage is room for numerous problems in plants.

Why does my potting soil stink?

The potting mix does come with an expiry date. The soil does not go bad, but the potting mix ingredients, such as peat moss, have a short lifespan of 1 to 2 years.

After this time, one should consider changing the potting mix to avoid the potting soil smell.

What happens when the potting soil goes bad?
Once the soil entirely uses the peat moss, the level of salt is increased in the soil and thus reduces the soil’s drainage.

Because of reduced drainage, the soil will not be able to drain water, resulting in the plant’s overwatering. Reduced water also means that the supply of oxygen is also reduced.

When the soil is overwatered, the plant is prone to root rot, and is room for lots of fungal and bacterial infections. This root rot, if left neglected, can destroy the plant.

Sometimes, we also notice mold being settled in the potting soil. This indicates that the water was not appropriately drained from the pot.

We can prevent overwatering and root rot by allowing the topsoil to dry out first and then water the plants thoroughly.

This also helps prevent the mold from being settled in the soil, which causes the potting soil to stink.

Also read: All about overwatering vs. underwatering

Can I still use a bad-smelling potting soil?

Soil is the most important factor that provides the nutrients and moisture for the growth of the plant.

The potting soil we use has lots of microbial activities and the fertilizer and the nutrients that we feed to the plant.

Usually, this potting soil can last for a year and a half. But what happens to the unused potting soil?

We can reuse the old and unused potting soil with these simple steps:

  1. Remove any plant matter available in the soil like any weed or roots.
  2. Spread the soil in a table and breakdown larger clots.
  3. The filtered soil should be sprayed with water on the uppermost layer.
  4. Dry out the soil in sunlight for about a week.
  5. The use of a plastic sheet after two days is suggested to avoid weed invasion and rain.

Also read: How and when to repot a plant?

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Checking the soil

After a couple of days, we will need to check whether our soil is ready to be used. For this, there is a simple hack.

Take a handful of soil and make a ball out of it. Now gently tap the soil ball.

If the ball falls apart, then the soil is dry and is ready to be revitalized.

However, if the ball retains the shape or has only a little dent, the soil needs to dry out more.

We can also use a soil pH test to test the soil’s nature, whether it is acidic or alkaline.

Adding some nutrients to the soil

Once the soil is dried out, and we have checked the soil’s nature, the next step is to add the required nutrients to the soil.

Add compost to the soil in a 1:1 ratio or at least 35%. We can also add 10% of neem cake powder to tackle with pathogens.

We need to make a universal potting soil; hence we can add all those ingredients like the coco peat, perlite, and pumice.

Mix everything well so that when we intend to use it, our plants get the right proportions of everything available in the potting soil.

If we do not want to use the potting soil right away, store it in a cool, dry place, away from dampness. Make sure that the humidity of the place is also low.

We now finally have our unused soil that is ready to be used again.

How do you know when soil is bad?

It is difficult to determine if the soil we use is good or bad. This is often tough and the worst situation for the plants.

An overwatered plant might develop a root rot quickly. If not, the plant is prone to attract pests.

We always want to know if our soil is healthy because it will help the plant grow and provide all the necessary nutrients.

There are several ways from which we can tell if the soil is bad or not working enough for the plants. Let us look at a few signs:

Amount of Nitrogen

Nitrogen is one of the most important chemicals required for the growth of the plant. It all depends on the amount.

Both excess of nitrogen and the deficit of nitrogen causes an issue to the plant.

For example, too much nitrogen causes the plant to wilt though it will give you lush foliage.

Similarly, too little nitrogen will cause a discoloration of leaves, and we will see the leaves shed. We can fix this by adding compost.

Moss on the soil

We often see moss on the upper layer of the soil. If the plant does not receive direct sunlight ever, then we can see such moss development.

Moss means that the acidic nature of the soil is high. We can add lime to reduce the acidic nature to a neutral level. Wood ash is also suggested.

Overwatered Soil

Overwatering is the most common reason for the soil going bad. In case the soil is not aerated and the water stands still, then there are chances of the soil going bad.

We should check the soil before watering. If the top layer of the soil is still mushy, then avoid watering the plant. Let the soil dry out first and then water the plant.

Root Development

To check the plant and the soil, we must check the roots. This will make sure that the plant is safe.

Pull out a strand of the plant and check the color of the roots.

If the color is white and crusty, then we can say that the roots are perfectly fine,

However, if it is black or brown, then there could be some problems with the soil.

How do I stop my potting mix from smelling?

The plant needs a bit of care when it comes to the soil.

Before we jump into the question of how to stop the potting mix from smelling, we will discuss how to prevent it.

The plant needs to be watered correctly to prevent the plants from being overwatered. Always check the soil before watering.

The perfect way of watering is by Feeling the soil. If the soil appears dry, water the plants thoroughly and allow the soil to dry out before watering.

If the plant is overwatered, then the soil becomes too moist and is very sticky and slimy, which might bring a root rot situation along with various pests and diseases.

Next comes the drainage situation. Maybe we are watering our plant perfectly, and we also have a watering regime.

It could well be that the soil that we are using does not have good aeration and is not well-draining soil. It could also be that the pot does not have a sound drainage system.

So, check if the pot has a sound drainage system available to prevent overwatering.

Next, if the soil is not well-draining soil, consider adding some pumice to the soil to increase its aeration.

Consider repotting your plant to a newer pot with well-drainage and use a good potting mix if the soil is terrible.

Now, let us jump to the part on how do I stop my potting mix from smelling?

If we notice any musty odor from the soil or see the development of any fungus or mold on the soil, then we might have to repot the plant in fresh soil.

We are sorry; however, there is no getting out of this situation. Also, we do not want our plants to grow in bad soil.

There is a consideration while repotting. Always check the roots before repotting. If the roots are not hard and crusty and are black, then it is probable that the roots have a rot situation.

In this case, we can try repotting the plant in a different pot to stop the spread. The plant might not thrive if most of the roots system is gone.

Giving it a shot is a good option than to neglect.

Lastly, blending activated charcoal (1/3 cup) with four quarts of the naturally fertilized soil along with a well-drainage system diminishes the smell in indoor plants.

How to prevent bad smells in the soil?

We have almost come to the end of the guide, and now we will tell you different additions to the soil that can help prevent the bad smell.

After following the perfect watering conditions and checking the drainage, we have eliminated almost 80% of the issues.

These are a few chemicals and compounds that can help prevent the bad soil smell:

  1. Compost/ sand/ peat: Compost, sand, and peat all these ingredients are best for the soil, as they increase the aeration in the soil and make it well-draining. This allows the oxygen to flow more effectively and thus reduce the foul smell.
  2. Phosphorous Content: If the smell of the soil is sour, then the soil lacks some essential elements. Often, Calcium and lime are used to change the pH level in the soil.
  3. Activated Charcoal: To increase the flow of oxygen in the soil, we can mix activated charcoal along with well-fertilized soil. This will reduce the bad-smelling soil and increase the drainage.

Also read: 9 Tips to grow your houseplant faster


Source: Microbiology Society, NRCS Natural Resource Planner

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