Mold on houseplant soil

Mold is a type of fungal growth mainly in moist and humid areas in your home. Molds spread with the help of spores. These spores are present everywhere, even inside your house. But they are completely invisible to the naked eye, so you can’t see them. That makes it virtually impossible to stop them from entering your house. There are two ways in which mold spores enter your house. They either come by air through open doors and windows, or enter your house by clinging to people, pets, or some objects. Molds are a big concern for every home. Even if they don’t destroy homes as termites do, they can cause discoloration and bad odor. Moreover, toxic mold or black mold (Stachybotrys chartarum) can pose health risks to the people who are exposed to it for a considerable period of time. They are capable of worsening the condition of asthmatic people and the people who have mold allergies. Also, they can cause respiratory problems in people who have weak immune systems, such as old people and infants. 

Mold On Houseplant Soil

Once the mold spores enter your house, they can find many suitable places to grow. There are many areas in your house that offer moist and humid environments for mold to grow. Some of the most common breeding grounds for mold in your house are as follows:-

  • On interior and exterior walls that have faced water damage.
  • Plumbing leaks.
  • Under the kitchen sink.
  • Mattresses
  • On carpets and upholstery
  • Drywall and insulation
  • Bath toys of infants
  • Potted indoor plants

Even though not all molds are toxic and harmful, you must remove any type of mold that grows in your house. If you ignore mold, it is capable of reaching extensive growth. In case it has reached extensive growth, you are advised to hire a professional mold removal service. A typical house wouldn’t have the equipment and expertise to remove a mold covering a large area.  But if the mold growth is only over a small area, you can remove it yourself with the right equipment, products, and the right techniques. 

      In this article, we are going to see the causes of mold growth in potted plants and how to remove them completely and effectively. But before that, the following are the types of mold that might grow on your houseplant soil:-

  • Yellow mold: Yellow mold is a kind of saprophytic fungi. Even though it is harmless, it should still be removed as soon as possible. You can simply remove yellow mold by purring the plant in another pot with sterile potting soil.
Yellow mold
  • White mold: There are various types of mold that appear in white color. The most common among the types of white fuzzy mold found in homes are Penicillium, Cladosporium, and aspergillus. This type of mold is generally harmless.
White mold
  • Grey mold: Just like white molds, grey mold is not a particular type of mold. There are several moles that have grey color. But one particular type of grey mold, called botrytis, is capable of harming the plant if you ignore it. Grey mold grows either in dense foliage or on the surface of the soil.
  • Sooty mold: Sooty mold is a term used for the various types of ascomycete fungi. It grows mainly on plant surfaces that are covered by honeydew.
Sooty mold


Due to the presence of moisture and humidity, potted plants provide a perfect breeding ground for mold. Following are the main causes of mold growth in potted plants:-

1.Lack of sunlight

One of the main causes of mold growth in an indoor potted plant is the lack of proper sunlight. Molds and all other types of fungi require darkness to grow. You won’t find them growing on surfaces that are directly exposed to sunlight. So keeping them under direct sunlight regularly for some time is an effective way to combat and prevent houseplant mold. 

2.Decomposing leaves

The decomposing leaves of your houseplant help in the growth of mold. They contain dead organic matter which is food for the saprophytic fungus in your houseplant soil. Dead leaves are often left on the potting soil after they fall off. If you don’t remove the fallen leaves from the pot, they might help mold is growing in the houseplant soil.

Decomposing leaves

3.Contamination of potting soil

Other than the causes mentioned above, the contamination of potted plants can also cause mold growth. If you don’t find any other reason for the growth of mold in your houseplant soil, it can be due to the potting soil being contaminated. Moreover, it can also be the case that the soil was already contaminated when you put it in the pot.

4.Poor circulation of air

Poor circulation of air in the houseplant soil can also cause mold to grow on it. Keeping the plant in a cramped place or corner causes poor air circulation in its soil. Due to the poor circulation of air, the plant-soil doesn’t dry out completely and remains moist. And this creates a favorable condition for the molds to grow. You will face this problem, especially during the winter months when the windows will be closed. 

5.Poor drainage

Poor means of drainage in the pot of a houseplant causes excessive moisture in it. This creates a suitable environment for mold to grow and thrive in. Lack of proper drainage in the pot may be caused by an unsuitable size. Many pots come with drainage holes in them for the purpose of aiding the water drainage. Lack of holes may also be a cause of mold growing on your houseplant soil. Yet another cause of poor drainage can be that the soil in the pot has more density than the suitable level for proper drainage.

4.Too much watering

Too much watering a houseplant can also cause molds on its soil. Since too much watering creates excessive moisture in the soil, it provides for a suitable breeding ground for mold spores. This problem is increased by the fact that houseplants have less access to direct sunlight than outdoor ones do. As a result, indoor plants must be watered less as compared to outdoor plants. 

How to get rid of mold from houseplant soil

Even though not all mold spores are harmful to plants, you must still get rid of any type of mold that grows on your houseplant soil. If you leave them untreated they will grow extensively. Moreover, the mold spores might scatter and find another suitable area for breeding and cause mold growth there. You can remove mold from houseplant soil quite easily by yourself and without any professional help. Following are the methods by which you can get rid of mold in your houseplant soil:-

1.Drying the potted plant in direct sunlight 

This is perhaps the simplest way to get rid of mold from your potted houseplant. You can kill off the mold, regardless of the type, by just placing it under direct natural sunlight. The UV rays of the sun effectively kill off all the mold present on the potting soil. You can do this in two ways:-

  1. Your plant might be sensitive to direct sunlight. In such a case, you can remove the plant from the pot and spread out the soil under direct sunlight. But you must be careful while removing the plant. This method is effective in killing the mold on the soil completely. Molds require a dark environment to grow and cannot survive in sunlight. That’s why you won’t see them growing on plants that are properly exposed to direct sunlight. You may use baking soda solution on the soil to absorb its moisture. You can easily make baking soda solutions domestically. You have to mix a quarter teaspoon of baking soda into a spray bottle with water.
  2. In case your plant can take being under direct sunlight, you can simply put the pot along with the plant at a suitably sunny spot. You may even remove the upper layer of the soil since this is the layer that has mold growth.

2.Repot the plant

Another simple method to get rid of mold from your plant soil is to report it. In other words, getting rid of the moldy soil and potting the plant in healthy soil. If you don’t want a complicated method and are looking for a very simple one, this method would be perfect for you. You must have sterile soil for potting the plant after getting rid of the moldy soil. You just have to follow two simple steps in this method:-

Repot the plant
  1. Remove the plant carefully from the pot and clean the pot thoroughly. You are suggested to spray fungicide on the pot in order to kill off any traces of mold left in it. There are suitable fungicides available in the market for this purpose. But you don’t necessarily have to use a fungicide. You can also use a bleach solution to clean the container. Simply soaking the pot in the bleach solution, consisting of  1 part liquid bleach and 9 parts water, for 10 minutes will do the job. After that, you can simply rinse it with a mixture of water and dishwashing liquid.
  2. After rinsing the pot with dishwashing liquid and water, it is ready to be filled with the new sterilized soil. But before potting the plant again, you must ensure that there are no mold traces left on it. If you still find mold in it, you are suggested to use a bleach solution to wash it once more.

It is necessary that you report the plant only after completely eliminating mold from the container. You must not ignore the traces of mold left in it. Otherwise, it would only be a matter of time before you find mold growing again on your houseplant soil. Also, you are suggested to spray fungicide on the plant before potting it.

3.Replanting the houseplant immediately after bringing it home

Replanting right after buying or receiving it from someone would also actually be a great idea. In other words, you can just remove the plant from the container that it was originally planted in. Then you can plant it in a new container or that same container after cleaning it. But you have to use a new sterilized soil containing peat moss, regardless of whether you’re using the same container or not. This would ensure that mold doesn’t grow on your houseplant soil, to begin with. This method would also be useful in making sure that you don’t unknowingly bring home container plants with moldy potting soil. This method is also effective in mold prevention in addition to mold removal.

4.Remove mold manually and spray with a fungicide

Manually removing the mold would also be as effective as the other methods described here. It is also very simple to do. You just have to follow these steps:-

  1. First of all, you need to scoop out the moldy soil surface. Make sure that you have got all of the soil surfaces that have been contaminated with mold. Otherwise, there would be a risk of the mold regrowing. The mold will keep regrowing by feeding on the dead organic materials until you get rid of it totally.
  2. After removing mold from the soil, you can then get on to removing mold, if there is any, from the plant. you can use fungicide for this purpose. And if you favor organic materials, you can go for cinnamon or neem oil. These two products are easily available and are effective in remediating the mold on the plant. After that, you can use a cloth or kitchen towel to wipe the plant.

5.Use organic anti-fungal products on the plant soil

There are various natural products that you can use to remove as well as prevent mold on houseplant soil. These include cedar, vinegar, baking soda, neem oil, and cinnamon. All these organic products are easily available. They are also effective in keeping mold at bay. Moreover, you would have to worry about your houseplant getting damaged in case of inorganic products. But you would be completely free of such worries while using these organic products mentioned here. So from that angle, organic anti-fungal products are better than inorganic ones.

How to prevent mold from regrowing in houseplant soil

There are so many effective ways to remove mold from your houseplant soil. But preventing the mold from growing in the first place would hand down be the best thing to do. So it would be an injustice to look at methods for removing mold while not giving space to the methods of preventing them from growing. So here are some simple ways to prevent mold growth on household plant soil:-

1.Provide direct sunlight to your houseplant regularly

Keeping your plant in a sunny spot is perhaps the simplest way to ensure that mold doesn’t grow on it. Moreover, it would also be beneficial for the health of your houseplant.

2.Don’t let dead leaves gather in the container

Leaving dead and decomposing plant leaves in the container would almost surely cause mold growth. As we have seen, decomposing organic matter is food for the saprophytic fungus.

plant on Sunlight

3.Use a sterilized potting soil

Another significant step in preventing fungal growth would be to pot the plant in sterilized potting soil.

4.Provide proper air circulation to the soil

Providing a proper circulation of air to the houseplant soil would be useful in preventing mold growth on it. To ensure proper air circulation you must use a potting soil that has a suitable density for the purpose. In other words, don’t pot the plant in potting soil having too high of a density. Also, if possible, you must arrange for proper air circulation in the room in which the plant is kept.

5.Provide proper drainage

You must arrange for a container with proper drainage. A lot of containers come with drainage holes for this purpose. Also, make sure to get a container of the right size, since that plays a role in the drainage quality as well.

6.Don’t water your plant too much

You must be very careful not to water your plant too much. As we have seen, watering it too much will cause excessive moisture and allow mold growth.

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