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White Powder on Clay Or Terracotta Pots (Here’s What to Do)

I get a lot of questions about a white powder that sometimes appears on terracotta or clay pots. 

Given the frequency with which this question has been raised, I’ve decided to write this article in an attempt to explain what this is all about, whether or not it affects the plant, and, if necessary, how to remove it.

In general, there are two reasons why a white layer forms on terracotta, clay, or ceramic pots. 

Due to the buildup of minerals on the surface, and white mold’s appearance on the surface.

My goal in this article is to help you understand why it happens in both cases, whether it harms your succulents, and how to clean your clay pots to remove them.

What Is The White Stuff on Outside of Clay Pots?

 White Powder In The Terracotta Pots
White Powder In The Terracotta Pots

Terracotta is a material that is porous and breathable. For succulents, it is one of the best containers for aerating the soil and allowing excess water to evaporate quickly.

Because of the pot’s breathability, certain irrigation water minerals build up on the outside. Over time, the white coating will get thicker and thicker, making it more noticeable.

Minerals like salts and lime, for example, will not be able to pass through the pot’s pores and remain on the outside of the pot’s surface. This is why it occurs.

How White Powder In Terracotta Pots Affects Succulents

Mineral accumulation on succulents is not harmful, so there is no need to be alarmed. 

However, it is best to remove it to avoid affecting the pot’s porous and breathable qualities. 

In contrast, excessive accumulation of this white layer makes it look unkempt and unappetizing.

How to Avoid White Dust on Terracotta or Clay Pots

Minerals are what cause white dust, so use irrigation water that doesn’t have any concentrated minerals in it.

White deposits on tap water are caused by the presence of lime, chlorine, and other chemicals, which vary from place to place. 

Try to avoid watering your plants with city water whenever possible to keep this problem at bay. You can use rain or filtered water for your plants as an alternative.

White mold

As previously mentioned, white mold could be the culprit. You can tell this mold apart from mineral buildup because it has a soft, cotton-like appearance, is moist, and forms a relief on the pot.

It is possible for this mold to change color if it grows too much and takes on a yellowish, grayish, or even black appearance. 

Humidity causes it to appear first in low areas of a pot or substrate. However, it can also appear on the soil’s top surface.

Humidity encourages the growth of this mold. Mold thrives in areas with a lot of humidity.

Because of this, white mold is more likely to appear or increase in the winter, during the rainy season, or when excessive watering occurs.

How White Mold In Clay or Terracotta Pots Affects Succulents

Generally speaking, this mold does not harm succulents. In excess or when it appears on the substrate surface, it can inhibit the growth of small succulents.

Keep in mind that mold is often a sign of overly humid conditions. You should cut back on watering if your succulents and cacti are suffering from mold.

However, white mold is a magnet for mold gnats. If there are too many of these insects and there is not enough food for them, they will start feeding on your plants, particularly the roots. 

Avoid having this white mold to avoid gnats.

How To Keep Terracotta Or Clay Pots Free Of White Mold

Mold will no longer be a problem for you if you control the humidity. As a precaution, I take the following measures:

  • We try to water more efficiently.
  • It’s best to place the pot in an area that gets a lot of natural light.
  • I use a dehumidifier indoors to remove humidity from the air.

How to Remove White Mold from the Potting Soil Surface

For the removal of white mold, you can use cinnamon powder. Just sprinkle it on the substrate and the white mold will be removed.

You can use decorative stones for succulents on the substrate if your succulent plant or cactus does not have white mold on the surface of the substrate and you want to prevent it from appearing. 

It is one of the many advantages of mulching for succulents that this white mold can be prevented.

What Is The Best Way To Clean Clay Pots?

Cleaning the terracotta or clay pot is a breeze. You can use a damp cloth or brush to clean the outside of a pot that has plants in it. 

Clean the pot’s exterior with a solution of water, vinegar, and baking soda. Do not use any harsh chemicals on your plants, as they can harm them.

In pots that don’t have any plants in them. You can use the same solution of water, vinegar, and baking soda for mold-infested pots if you want to reuse them (in this case you can use a little detergent, soap, or bleach in the solution). 

After that, use a cloth to wipe down the surface and a brush to scrub it, and then rinse it all down with water.