White Mold on Terracotta Pots – How to Get Rid of It

There are many advantages to using terracotta for pot plants. Its porous properties allow it to absorb water from the soil, helping to prevent it from becoming waterlogged. However, these properties can result in aesthetic issues, such as water stains and mold on the terracotta pot.

Some homeowners like stained terracotta pots, which create an aged, rustic appearance. But, it would be best if you took notice of any mold that may be developing on your pots, as the presence of mold may indicate underlying problems in your planter.

Mold on Terracotta Pot

In this article, we will explore:

  • what type of mold is growing on your terracotta pots,
  • understanding the risks and dangers,
  • why it is growing, and
  • how to effectively clean it off your pots.

Is it Mold on Your Terracotta Pot?

Mold vs Mineral deposits

Before we get into all things related to mold, we think it is essential to identify whether you have mold growing on your pot.

You may immediately assume any white marks growing on the exterior of your terracotta pot is mold. However, you may be relieved to hear that not all white substances are harmful.

In addition to white mold, mineral salts can accumulate on the exterior of your pot. Unlike plastic or ceramic pots, water can pass through terracotta. This brings other soluble items like minerals from fertilizers and in your tap water (if you use tap water to water your plants). As the water evaporates, the minerals solidify on the terracotta pot and form a crust.

Here are methods for telling the difference between mold and mineral deposits:

  • Touch the white marks on your terracotta pot – Mineral deposits will feel grainy and dry, and your touch will not change the appearance. At the same time, mold will feel furry and damp. You will also leave imprints where you touched the mold, as the pressure of your finger will damage the spores.
  • The appearance of the white substance – Look at the profile of the white marks. Mold will appear raised, while mineral deposits will be level with the terracotta’s surface.
  • The growth pattern – Mold generally begins growing as spots dotted around the moist areas on your pots. It may start forming patches as it increases, but the growth is usually circular. At the same time, mineral deposits will appear as more random patches with no discernable growth pattern.

What is the Mold Growing on my Terracotta Pots?

The type of mold that grows on terracotta pots is fungal.

It requires moist and humid environments to grow. When the atmosphere dries out, the mold will die off. However, spores will remain dormant, waiting for conditions to become ideal again. To eliminate the mold, chemical treatment is required – more on that later.

Is it mold or mildew?

According to the United States Environmental Protection Agency, the difference between mold and mildew is a matter of reference.

Mold is more of a collective term that is used to refer to varying types of fungi species.

While mildew is generally used to refer to the growth habit of the mold.

Can I Leave Mold on Terracotta Pots? Is it Harmful?

Mold is harmful to humans when inhaled. Therefore to ensure the safety of you and your household occupants, we recommend chemically removing the mold from your terracotta pots.

Like mushrooms, mold produces spores that can become airborne when disturbed. It is their reproduction method so they can spread to other damp areas of the house. While they are traveling through the air, we can inhale the spores.

The inhaled spores can trigger symptoms like stuffy noses, irritated eyes, and skin problems. In severe cases, the mold can sometimes travel into our lungs and produce an infection.

Note – the mold will not harm your plants.

How to Get Rid of Mold on Terracotta Pots

Mold on Terracotta Pots

So now that we know how harmful mold can be to humans, how do we eliminate it from our terracotta pots?

You can use several methods to clean mold from your terracotta pots.

Clean Your Terracotta Pots with Bleach

IMPORTANT – we only recommend using bleach if you have empty terracotta pots.

Bleach is toxic and is effective at killing mold. However, even if you are only using it on the outside of your terracotta pots. It can still pass through the porous material and kill your plants and the beneficial microorganisms in the soil.

Once you have removed your precious plants from the moldy planters, follow these steps:

  1. Pour 1 part bleach with 20 parts water into a spray bottle and shake vigorously. Remember, do not use a spray bottle that you use on your plants.
  2. Apply generously to the affected moldy areas. In addition, coat the entire pot (inside and out) to ensure no other spores. Allow soaking for 10 minutes.
  3. Scrub vigorously with a hard bristled brush and spray down with fresh water from your garden hose.
  4. Soak your pot to flush out any remaining bleach.
  5. Repeat soaking until the chemical smell no longer remains.

Congratulations – you have successfully sterilized your terracotta pot.

Clean Your Terracotta Pots with Hydrogen Peroxide

This is our preferred method for cleaning terracotta pots still in use. But, there are still some precautions that need to be taken. Otherwise, you can still damage your beautiful pot plants.

Only use hydrogen peroxide, which is 3% strength. Any solution with a higher percentage can potentially cause damage to your pot and plant.

To use hydrogen peroxide to clean your terracotta plants, follow these steps:

  1. Pour 3% hydrogen peroxide into a spray bottle.
  2. Generously apply to the moldy areas on your terracotta pot.
  3. You should begin to see the hydrogen peroxide reacting with the mold. Bubbles will start to form on the wet areas, killing and lifting the dirt from the terracotta.
  4. Scrub the sprayed down areas with a stiff, bristled brush.
  5. Spray down with fresh water from your garden hose.

Continue to apply hydrogen peroxide until you are satisfied the area has been sufficiently cleaned.

Clean Your Terracotta Pots with Vinegar

The last method of cleaning we will discuss is vinegar.

Like bleach, when cleaning terracotta pots with vinegar, you must remove any plants and soil before you begin. Vinegar is a natural herbicide and will harm your plants.

To clean terracotta pots with vinegar, follow these steps:

  1. Find a container large enough to be able to submerge your terracotta pot.
  2. Clean your pot from any loose soil before placing it into the container.
  3. Add a mixture of vinegar and water that has a one-to-one ratio (one part vinegar to one part water). Fill until your pot is completely submerged.
  4. Soak for 30 minutes. Remove the pot and scrub any marks that remain on your pot with a stiff-bristled brush.
  5. Repeat the soak until you are satisfied with your pot.
  6. Wash your pot with fresh water from the hose and allow it to air dry before using.

How to Prevent Mold from Growing on Terracotta Pots

Stained Terracotta pot

Now that we know how to identify and clean your pots. Let’s now turn our attention to prevention.

There are a few things you can do to prevent the growth of mold on your terracotta pots.

Here are our top tips:

  • Don’t overwater – mold requires constant moisture to grow and multiply. Without water, it will not survive. Overwatering your plants keeps the terracotta constantly wet, which is the ideal breeding ground for fungi.
  • Maintain excellent drainage – ensure your terracotta pots have excellent drainage to allow any excess water to escape. If the water is allowed to drain away, the terracotta will not be able to absorb enough water to harbor mold.
  • Proper airflow – without adequate air circulation, the water absorbed by the terracotta will not be able to evaporate. And once again, mold will begin to grow if the terracotta remains sufficiently moist.