How To Clean Mold On Terracotta Pot (Black Mold-White Mold)

Last Updated on June 15, 2023 by Grow with Bovees

Terra cotta pots are great pots to use for the cultivation of container plants.

They make for incredibly natural and beautiful plant homes both for indoor and outdoor plants.

And they also happen to be great for starting cuttings.

Terra cotta pots are, however, well known for the growth of white fuzzy looking mold and crusty white residues, which can be quite off-putting at times. Although this white mold development will not hurt your plant, it may be harmful to your health.

In this article we shall take you through everything you need to know about moldy terra cotta pots and how to get rid of this growth.

But before we continue with the mold situation, let us take you through the amazing benefits of making use of terracotta pots.

Benefits Of Terra cotta Pots

Although terracotta pots are starting to become less popular, I find that we should appreciate them.

These lovely bits of clay have been around for a long time.

They are a great environmentally friendly choice when wanting to reduce the use of plastic in your garden or in general even.

Houseplants Love A Clay Pot

Terracotta pots — unlike plastic pots or other plastic containers — are porous and can actually breathe.

Terracotta absorbs moisture, so overwatering is quite hard, as excess water will slowly seep through the pot, preventing the roots from drowning. This makes your plant thrive better as conditions are rarely overly wet.

Also, when the terra cotta pot is moist, it turns to a darker color, which means you can always tell when you need to go about watering plants.

Shapes & Sizes

It is quite fun to work on tiny garden collections by using terra cotta pots as they come in plenty of different shapes and sizes. They range from large terracotta pots to smaller pots.

Reusable

Terra cotta pots unfortunately tend to break or crumble, especially when left outside during the colder months of the year. Place your pots in a greenhouse or in your house to avoid this.

If you happen to sit with broken terracotta pots, remember that they are fun and easy to reuse. Place them into bigger pots or gardens for added decoration, giving it a lovely rustic feel.

The Weight

Terra cotta pots tend to be quite heavy in mass — especially larger planters. This is a great advantage when you are cultivating top heavy house plants. The risk of toppling over is minimal due to the weight of the pot.

Now that you know more about these pots, let us continue by talking about their common discoloration.

Reason For Mold Growth

Terra cotta pots are the perfect growing surface for mold because they absorb moisture from the soil.

These pots almost never dry out. Moist conditions due to poor drainage make for an excellent mold-growing environment.

Placing your clay pots in an area which is generally darker, with little flow of oxygen and more humid, will keep the pot moist for longer, which speeds up the growth of fungus.

The fungus will present as a white fuzzy growth on the sides and rim of your pot. It can also appear as a black mold.

Some Cleaning Methods

There are some different cleaning processes to choose from when wanting to get rid of mildew or remove mold from clay pots. They range from natural methods to chemical methods.

Step By Step Guide

Let us get you started off with a few simple steps to take before applying any sort of disinfecting or cleaning solution.

Get rid of old plants and soil from your pot.
Give the excess soil a moment to dry, this will make it easier to get off.
Use a scrubber such as steel wool and remove as much dirt as possible.
If you deem it necessary, wash out the pots inside using clean water. Don’t use soapy water, as it often leaves residue which is hard to get rid of.
If you notice a white crust on the sides of your pot, make a water and baking soda paste and rub it on the white crust. Then use a brush to clean it off. This white crust is often a result of the salt found in fertilizer and water.
Lastly, rinse the container and allow it to dry.

Continue on to learn about the different solutions you can use to get rid of mildew growing on your terracotta pots.

Cleaning Method One — Hydrogen Peroxide

This is the first and easiest method to kill mold growing on your planters. Use 3% hydrogen peroxide (safe for plants), and simply apply thin layers to the outside surface of your planters by means of a spray bottle. Spray directly onto the mold location.

Allow the chemical to work for a few minutes. You will notice hydrogen peroxide sizzling when it starts working. Soak the pot in water and physically scrub off the mold and remaining fungus.

Do not expose hydrogen peroxide to light. Light exposure will rid the chemical of its effectiveness and will not kill the mold.

Cleaning Method Two — Bleach

Using bleach is another effective way of getting rid of mold. Add one part of bleach to a spray bottle and combine it with 20 parts of water.

What is important to remember, is that bleach is quite a strong toxic solution, so remove the whole plant with its root ball from the pot before applying it. You can place the plant into a temporary pot while you are applying bleach.

Spray the outside of the pot with the bleach and water solution. Scrub off as much mold as you can and then soak the pot in water in order to remove the remaining bleach from the pot.

Soak clay pots a few times to ensure the proper removal of all the leftover bleach mixture.

To finish this process, let the pot air out and dry for a couple of days. Make sure that the smell of bleach has disappeared completely from your decorative pot before repotting your plant.

Cleaning Method Three — Baking

If you don’t want to make use of peroxide or bleach, try making use of heat.

Again, start by removing as much loose dirt as you can from your container.

Now place it in an oven. Place some aluminum foil at the bottom of your oven to protect it from any excess dirt falling off.

Set the oven heat to 220 degrees Fahrenheit and leave the planter to bake for a minimum of one hour. This will kill any damaging growth.

End the process by switching the oven off and setting the pot to cool off. This takes time but is crucial to preventing burn wounds.

Getting Rid Of Black Mold

Here’s a quick guide to remove the layers of mildew from your clay pots.

Make a homemade mixture of equal parts white vinegar and water. You can use any container of your choosing, but I’d say a spray bottle is optimal.

Spray the white vinegar mixture onto the sides of your containers.

If you only have a mild case of mold, then this action should be sufficient. The solution should be left to dry on its own, and it will kill the mildew in the process.

If you notice that the mold is still there after the spray has dried, reapply the solution a second time. Scrub your pot again using a cloth or soft brush.

Continue the process by rinsing the area with water after scrubbing it and applying another layer of spray, then allowing it to dry.

Getting Rid Of Green Mold

Let us look at the basic steps to removing green mold from your terra-cotta plant pot. You can do this in three easy steps.

Begin by removing any excess loose dirt from the planter using a tooth brush or soft scrub brush. You can use a pot brush to brush off as much soil from the pot as possible.

Next, apply a good amount of the water/vinegar mixture and allow it to soak the container.

And lastly, place the soaked pots in the dishwasher and run them through the quick wash cycle once.

Preventing Mold

Using the natural effect of the sun is a great way to prevent the growth of mold on clay containers.

However, placing your plant pots in direct sun should only be done if your shrub can tolerate these conditions.

Provide direct sun, exposing the mold and ultimately killing it.

Good and increased air circulation also factors in and aids in the prevention of mold growth.

What Is The White Residue On Terracotta Pots?

As discussed above, terracotta pots absorb water from the soil, which is great in the prevention of overwatering your house plants.

Terracotta pots also have the habit of absorbing fertilizers along with chemicals and salts found in tap water.

After a while, these elements are absorbed by the pot, creating a white chalky build up which forms a crusty residue on your clay containers.

This white crust is just the minerals and can be prevented by using rain water or filtered water rather than normal tap water. Using organic fertilizers rather than chemical fertilizers will also help. Organic compost solution is also good to use.

Not only is rainwater and organic fertilizers great for preventing white crusty residues, but they are also much healthier for your plants and for the environment. A win-win if you ask me.

The Difference Between White Mold And Mineral Deposits

If you find a white deposit on your terra cotta pots or in your potting soil which looks fuzzy, lightly scrape it off manually using your fingers. If it easily comes off, you can take it as a sign of white fuzzy mold growth.

Mineral deposits will not come off as easily, and it is not fuzzy looking.

White Powdery Mildew

This is a fungal growth found on plants caused by prolonged elevated moisture levels during the night and too dry conditions during the day.

It is easily identified by its whitish grey fuzzy blotch-like appearance on leaves and other parts of the plant.

White powdery mildew is harmful to your plants and to you. It is fast spreading and should be dealt with in a timely manner.

Is Mold On Clay Pots Harmful?

Mildew growth on the outside of your beautiful terracotta pots does not pose a threat to your greens. It is, however, quite harmful to humans and their health, especially if exposure is prolonged.

White mold produces spores which are easily inhaled by humans. People that have a sensitivity to mold might have symptoms such as itchy eyes or skin, or a stuffy nose. More intense reactions should be expected in people that have severe allergies, asthma or compromised immune systems.

Therefore, we recommend removing mold from your terra cotta pots by using any of the above methods as soon as you notice its growth.

Importance Of Cleaning Your Crusty Clay Pots

While some people have found a liking to the old crusty look of dirty terracotta pots, reusing them without cleaning them is quite unhealthy for your plants.

Cleaning your terracotta pot is a great habit to adapt to, as dirty pots make good grounds for harboring diseases and pests.

Combine repotting your plants with cleaning your pots. Clean pots and fresh potting soil are great to maintain the healthy growth and appearance of your shrubs.

If you do insist on wanting that old rustic look of a dirty terracotta pot, rather do so by painting it to look that way. This way, you get the best of both worlds, clean and rustic looking clay containers.

Conclusion

There you have it, just a few paragraphs about mold in clay pots. Mold readily grows on the outside of the pots.

With the above information, you should now be able to identify molds and white residues and be able to clean them off of the outside of the pots effortlessly. Kill molds with hydrogen peroxide and create a healthy environment for you and your plants.

Prevent white mold by improving air circulation, maintaining adequate drainage to avoid excess moisture and occasionally treat your pots with hydrogen peroxide.

So go and inspect your terra-cotta pots and clean them and, if you have severely affected plants, add fresh soil if necessary. Do it for the health of your plants and for the health of you and your family.

Don’t forget to have fun!