Is there mold growing on your houseplants? What you need to know

Anything kept in an environment with moisture and limited ventilation is susceptible to mold. And, unfortunately, that includes your plants. Mold on indoor plants is more common than you might think, and there are ways to get rid of it and prevent future recurrences. So, if you have a plant with a little mold, don’t give up just yet!

Why does mold grow on leaves and soil?

To understand how mold develops, we need to look at why mold occurs on the leaves and soil in the first place. The most common type of plant mold is a white mold in potted soil that develops on the surface due to things like inadequate drainage, constantly wet soil, and poor ventilation. This mold is relatively harmless most of the time; however, white soil mold does indicate that there is a larger issue with your plant’s environment that needs to be solved.

Another common mold that can affect your indoor plants is powdery mildew, which often shows up on the top sides of leaves. This mold is made up of spores that give the greenery a dusty appearance. Luckily, these spores are most often transferred in the wind when found outside. That means that unless you have an incredibly drafty space, the mold is less likely to go from one plant to another; however, keep in mind that it is still possible. So, you’ll want to remove this mold as quickly as possible once you identify it.

A potted ivy houseplant
Manja Vitolic/Unsplash

Identifying the plant mold

Mold on indoor plants will present differently depending on the type it is. There are kinds that affect the soil, kinds that affect the foliage, and kinds that affect a mixture of both. Luckily, none of them are particularly difficult to identify so long as you’ve been monitoring your plant regularly. Otherwise, they could easily fly under the radar until it’s too late.

  • Powdery mildew: Powdery mildew appears as small white spores, often giving the leaves of your plant a dusty look. It will often start on the tops and bottoms of leaves; however, powdery mildew can eventually spread to the stems and fruits/flowers of the plant as well, causing long-term damage like twisted and disfigured foliage.
  • Gray mold: Gray mold also has spores that are dusty in appearance; but unlike powdery mildew, gray mold will initially affect the parts of the plants that are near the surface of the soil. It often infects plants that are already suffering from damage and have dead tissue that the spores can land in and thrive. Infected areas have the potential to grow very quickly.
  • Sooty mold: Sooty mold can be identified by dark green to black sooty-looking patches that appear around the base of the plant and on the surface of the soil. This kind of mold often presents when a plant is infested with sap-feeding insects, and the patches could have a negative impact on your plant’s process of photosynthesis.
  • White mold: White mold is fuzzy in appearance, similar to the kind of mold you might find on food that goes bad, and grows on the surface of the soil. This kind of mold lets you know that the conditions of the soil are too damp for your plant, but it’s relatively harmless overall.

Removing mold from your plants

How you remove the mold from your plants will vary depending on the kind of mold you’re looking to tackle. Although each of them affects plants, they’re caused by different things and as such require unique approaches to manage the situation. Some have more simple solutions while others will need a bit more patience.

Powdery mildew

If your plant is suffering from powdery mildew growth, you may need to move it to a brighter location in your home. This type of mold grows well in shade, so increasing the amount of natural light (or artificial light via grow lights) will help prevent the mold from spreading while you work to clear it up.

If it’s a small amount of powdery mildew, you can attempt to try watering from above so that the water helps clean the leaves. Keep in mind, though, that this may not resolve the problem fully and shouldn’t be heavily relied on, as too much water on the leaves can have adverse effects. An approved fungicide should be able to clear it up nicely.

Gray mold

Gray mold is a bit more complex, since the plant it infects will likely already be diseased or have some damaged/dead tissue. Plants suffering from gray mold should be immediately isolated once you realize there’s a problem, and you should begin to remove any damaged or dead tissue from the plant with a pair of sterilized shears or scissors.

Once removed, apply an approved fungicide to the plant while following the directions on the bottle. Depending on the specific fungicide used, you should reapply every one to three weeks until the mold is gone.

Sooty mold

The process you follow to remove sooty mold will be determined by the size of the infestations. If there aren’t a lot of sap-feeding insects, you can simply remove them either with your hand or a pair of sterilized tweezers. If there are a lot of them, though, you’ll need to apply an insecticidal soap, making sure to follow the directions carefully. Once the insects have been taken care of, you can use a clean cloth, dampened with either water or a diluted soap solution, to clean off the sooty patches and rinse the leaves.

White mold

Fuzzy white soil mold, since it’s relatively harmless to your plant, has the easiest solution. Simply scrape off the infected part of the soil (if there isn’t a lot of white mold) and you’re good to go! With a larger amount of white mold, it would be best to repot your plant in fresh soil. Unfortunately, since mold spores exist naturally in the potting soil, there isn’t any way to fully remove the presence of white mold.

A small potted plant with green leaves
Severin Candrian/Unsplash

How mold affects those with allergies

Mold on indoor plants has the potential to cause the same allergy symptoms as other molds: itching, sneezing, congestion, dry skin, etc. Because these molds are indoors, the symptoms can be experienced any time of the year as long as the disease is around. Like other types of molds, powdery mildew and white molds can trigger asthma if they reach the lungs or breed for a lengthy period of time.

As such, you never want to take a chance when it comes to mold on indoor plants. If you have a mold allergy, take all the precautions you need to clear it up, even if that means throwing away the entire plant. Molds can be cleared up and treated, but not even a plant is worth risking a severe allergic reaction.

Preventing future problems

Whether you’ve experienced mold on indoor plants or not, it can be beneficial to know how to prevent mold on soil and foliage. Mold often thrives when the plant has received improper care or isn’t in the best condition. Keep an eye on your plants, checking them every day or two to make sure they’re doing okay. Maintaining proper care is key to prevent future mold on your indoor plants.

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