Sooty mold on a leaf.

How to Get Rid of Sooty Mold on Houseplants

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Have you been having problems with black or gray film on your leaves, stems, and flowers?

Sooty mold is a fungal growth that can weaken plants by blocking sunlight. It can be caused by pests or environmental factors. If you have a sooty mold problem, this article has tips on how to get rid of it.

Follow our tips in this article and you’ll be able to get rid of your sooty mold problem in no time!

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What is sooty mold?

Sooty mold is a type of fungus that grows on plant leaves, stems, and flowers that have a sticky substance, called honeydew on them.

This honeydew is created by insects that feed on plant sap. The honeydew then is a food source for sooty mold.

Symptoms of sooty mold

Sooty mold on a leaf.

The main symptom of sooty mold growth is the presence of a dark gray or black coating on the leaves of your plant. It can also sometimes be on the stems and flowers of the plant. It looks just like soot on your plants, hence the name, sooty mold.

How does sooty mold damage plants?

Sooty mold damages plants by blocking the sunlight. It covers the leaf surface with a black velvety coating, making it almost impossible for that part of the plant to get sunlight.

This reduces the plant’s ability to photosynthesize and can lead to the plant’s death.

How does sooty mold spread?

Sooty mold spreads when insects that feed on the sap of plants excrete honeydew. The honeydew falls on leaves, stems, and flowers, and the sooty mold fungus grows on it.

Is sooty mold harmful to humans?

No, sooty mold is not harmful to humans.

How to get rid of sooty mold

If you have sooty mold on your plants, there are a few steps to get rid of it. While you are treating the infected plants, you should quarantine them away from your other plants to prevent further spread.

Control the pests that produce honeydew

The most effective way of getting rid of sooty mold is to get rid of the source of the problem. The first thing you need to do is to figure out the insect problem on your plant. Which houseplant pests do you have producing honeydew on your plant?

Check all parts of the plant with sooty mold looking for signs of other pests. Once you know what is causing the honeydew, you can treat the plant for those pests.

Which pests produce honeydew?

The most common pests that produce honeydew on houseplants are aphids, soft scales, and mealybugs.

These pests are all large enough to see when checking your plants and look different enough, it should be easy to identify which one you have once you have found them. The links above have pictures, as well as recommended ways of dealing with these pests.

Wash sooty mold off the plants

Once you have controlled the pests, the next step is to wash the sooty mold off of your plants.

To do this, you will need to mix 1 TBSP of mild dish soap, like the regular Dawn dish soap, with 1 gallon of water.

Then spray the soapy water mixture on all of the affected leaves and let it sit for 15 minutes.

Finally, rinse the soapy water off by spraying it with a strong stream of water. This may need to be repeated once a week for a few weeks until all of the sooty mold is gone.

Apply neem oil

Another way to get rid of sooty mold is to apply neem oil. Neem oil is a natural product that will kill the fungus without harming your plants.

To use neem oil, mix according to the directions on the bottle and spray it on the leaves of the plant. Make sure to get all of the leaves, even the underside, and any parts of the stem that have signs of sooty mold or other pests.

The advantage to using neem oil is that is helps with the major pests that produce honeydew as well as helping to get rid of sooty mold.

How do I prevent sooty mold?

The best way to prevent sooty mold is to have a regular routine of checking your plants for pests and treating them accordingly.

If you find any pests, be sure to treat the plant right away. The sooner you can get rid of the pests, the less honeydew they will produce and the less chance there is of sooty mold.

Even if you get control of the pests quickly, make sure to clean the leaves to get rid of any honeydew that was left by the pests.


Sooty mold can be a big problem for houseplants, as it damages plants by blocking sunlight and preventing them from photosynthesizing.

The best way to get rid of sooty mold is to control the pests that produce honeydew and then wash the leaves with soap and water. If there is still some sooty mold present, you can apply neem oil to kill the fungus. Prevention is key, so make sure to check your plants regularly for pests and treat them accordingly.

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