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Why Do You Have Yellow Mold In Plant Soil? 6 Root Causes

Yellow mold in plant soil is one of the most common problems. The yellow mold in plant soil is called yellow slime mold or yellow houseplant mushroom. But where does the yellow mold in plant soil come from and how to prevent it?

We will reveal the answers to help you with your gardening. Now, let’s get started!

Where Does Yellow Mold In Plant Soil Come From?

The yellow mold in the plant soil appeared due to overwatering or the soil being infected. Let’s see the explanations of these reasons that cause yellow mold below.


The mold may develop for many reasons, the first of which is when the potting soil is excessively damp, allowing it to flourish. Excessive water causes moldy soil layers. Hence, the molds have an ideal environment to reach their peak

Infected soil

Your pot plants may sometimes turn yellow when purchased from a florist or garden shop. When you fill your pots with infected soil or planting mix, you risk unintentionally adding contaminants. When the conditions are perfect for these germs to grow and increase, yellow fungus or spots will appear in the potting soil of your potted plants and garden beds.

Poor light

Plants don’t grow well in low-light environments, but mold, mainly yellow mold, flourishes in them. Your bathroom’s pot plant will provide a perfect habitat for the germs to grow. The plant is likely getting too much humidity and is in a low-light setting with little or even no UV light or sunshine to destroy the mold.

In the landscape, garden beds surrounded by tall trees receive little light and are excellent breeding grounds for bacteria. Mold may sprout on tree roots, behind exposed brickwork, and even among your beloved plants, which prefer low light.

Fertilizers with contaminants

Mold spores can form due to fertilizer, such as compost or organic fertilizer. The germs can sprout in such nutrient-rich conditions.

Lack of aeration

Aeration of the potting soil is essential because it gives room in your potting medium for oxygen to access your roots. Mold may grow in the soil if there isn’t enough air. Moreover, make sure you apply the fertilizer appropriately. If you have a lot of fertilizer in one spot, mold may form there. It is necessary to use the correct fertilizer mix evenly.

Waterlogged soil

The last factor that leads to the formation of yellow fungus is when the earth becomes waterlogged. This problem not only creates a damp environment that is perfect for the fungus to thrive in, but it also suffocates the earth, reducing excess oxygen. Mold is a fungus that flourishes in low-oxygen settings and may even thrive anaerobically without any oxygen.

What Is Yellow Mold?

Fuligo Septica is the right name for this mold found in plant soil. It’s similar to seaweed and isn’t dangerous to people until you take a teaspoon. This mold has the potential to be unsightly. It can hurt plant stems and roots. Moreover, humans can suffer from bacteria. If your kids and pets eat the contaminated soil, tragedy happens.

How To Eliminate Yellow Mold?

How do I get rid of yellow mildew, and yellow fungus in my soil? Thankfully, there are many methods you can try to deal with this problem.

Vinegar or baking soda

If the plant attracts mildew, you can use fungicides to treat it. Nature offers us some fantastic solutions. You can mix apple vinegar with water. Then, spray the solution on the base of the earth and your plant. You might also add some neem oil, which is an excellent fungicide that would not harm your crop. Applying cinnamon powder to the topsoil. This tip will help keep fungus spores at bay. Additionally, your garden will have a pleasant odor.

Repot the plant

Although there is only a small spot of infected soil, you can repot the plant at this stage. This method aids in the elimination of as much fungus and its spores as possible. Replant your plant in a sterilized potting mix after clearing the old soil. If the infection isn’t too severe, lay it out in the sunlight and let it dry before treating it with fungicide.

Scrape it off

Scraping mildew from your plant soil is the simplest and most basic treatment method. Mold can grow to less than two inches, making it easy to scrape and scoop out. You must take extreme caution since the polluted dirt should not return. If you decide to use this technique, clean your plant afterward. Then, use a wet towel to eliminate mold. After that, destroy any residual mildew in the earth or on the plant using an antifungal.

Remove debris

Debris on topsoil is another source of fungus development. It can grow if fallen leaves and other waste still linger on the earth. The breakdown of dead leaves or other debris raises moisture levels. Consequently, it promotes perfect conditions for fungus to thrive and spread. Make it a habit to clear any debris off the topsoil before watering your plants. Also, avoid throwing food or drinks on the soil of your plants. For example, coffee grounds can promote fungal growth in plant soil.

How To Prevent Yellow Mold From Reappearing?

Yellow slime mold or the yellow houseplant mushroom are not the culprits when you detect yellow fungus in soil or yellow mold on plant soil. Here are some practical tips for preventing fungus, or yellow fungus, from reappearing in your plants.

Proper lighting

Plants may combat illnesses if you provide them with a healthy environment. They require light for photosynthesis to grow. Change the position of your plant if it isn’t getting enough sunlight. Mildew may attack plants that are in a gloomy or shady setting. Sunlight aids in drying the earth between waterings and helps avoid microbial contamination. As a result, if you have a low-light indoor plant, take special care of it.

Proper watering

Overwatering is one of the most common causes of fungus in planting soil. As a result, make sure to water your plants as instructed. In fact, underwatering is still preferable to overwatering. Overwatering will cause root rot as well. However, it would help if you watered thoroughly rather than shallowly.

Avoid organic matter

Organic fertilizer is an ideal choice for your houseplant since it is safe for plants, animals, and the environment. On the other hand, this fertilizer may contain unidentified organisms and illnesses that you are unaware of. As a result, be sure that any organic fertilizer is free of fungi before using it. They might be harmful to your garden.

Use natural fungicides

Using an organic fungicide to remove mildew from the earth is one of the simplest methods. Most natural substances, such as vinegar and neem oil, are antifungal by nature. Hence, they can prevent microbial contamination.


Do not panic if you find yellow mold on your plants. The bacteria won’t ruin your garden. Unfortunately, once ingested, it turns out to be dangerous. As a result, it’s critical to remove this fungus as soon as you notice it in your garden. Hopefully, the tips we have shared can make your gardening easier. If you need any further information, please feel free to ask. Thank you for reading!


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Kelly Lawrence

Kelly Lawrence

Kelly Lawrence is the CEO of Swipe Garden. Over 10 years in the writing and passion for gardening, she brings a wealth of expertise and creativity to the world of gardening. Kelly Lawrence has cultivated a community of plant lovers, making gardening accessible and enjoyable for all.