5 Top Causes Of Yellow Mold In Houseplant Soil

Bright yellow mold growth is visible amidst the dark soil and green plants, indicating fungal activity in a moist environment.

Indoor plants not only beautify the environment but also help to reduce stress, boost productivity, and improve concentration. The only challenge that indoor plants pose to their owners is maintenance.

Maintaining houseplants is challenging as you have to water, fertilize, and ensure they receive the right conditions to thrive. Even after doing all of these, pests, diseases, and even fungi might attack your precious indoor plant.

Another culprit is the yellow fungus.

In this article, we’ll talk about the yellow slime mold in houseplant soil.

If you discover yellow mold in your houseplant, you should not panic at all. Just like white mold, yellow mold is not dangerous to your plants. Of course, unless digested. Furthermore, it can be dangerous to your kid and pets if consumed.

For this reason, it is crucial to get rid of this mold as soon as you spot it in your houseplant.

Why Does Yellow Mold Develop On Houseplant Soil?

For yellow mold to develop on your houseplant soil, you’ve to provide it with the ideal conditions to prosper. Many gardeners and florists are usually surprised when they wake up one morning and find yellow mold on top of their houseplant soil. This is not a coincidence as a number of things lead to the development of the mold.

These are as follows:

1. Contaminated Soil

If you’re doing everything right, from watering your houseplant properly to ensuring it receives enough sunlight, you shouldn’t have a yellow mold problem. In such a case, the soil may be contaminated. Some soil dealers are not reliable as they may sell you contaminated soil.

That’s why it is highly recommended to purchase potting soil from a reliable source. If you buy contaminated soil and use it for potting, it is just a matter of time before the mold shows up.

2. Overwatering

Another common mistake that many gardeners make is overwatering their indoor plants. When you overwater your plants and create a damp environment, you create a conducive environment for mold to thrive. It only requires 24 hours for mold to start developing when the conditions are right.

3. Poor Light

Houseplants that don’t receive enough sunlight may also develop yellow mold easily. Light inhibits mold growth; thus, they will develop well in places that don’t get enough light. For instance, yellow mold can develop easily in houseplants that are far away from the window or in dark places.

4. Fertilizer

Using organic fertilizer in your houseplant is a good idea as it is not harmful to the plant, pets, and even the environment. However, organic fertilizer may be carrying some unknown organisms and diseases that you may not be aware of. So, before you utilize certain organic fertilizer, ensure that it is free of mold or fungi. These may cause trouble for your houseplant.

5. Lack Of Enough Aeration

Soil aeration is Important as it creates space in your potting medium where oxygen can easily reach your roots. Therefore, if your soil does not have air, this may promote mold development in the soil. Furthermore, you should add fertilizer correctly. If fertilizer is concentrated in one area, this may invite mold into that place. The right fertilizer mixture has to be applied evenly throughout the pot.

How To Get Rid Of Yellow Mold In Houseplant Soil

1. Proper Watering

As highlighted above, overwatering is one of the main causes of mold in potting soil. Therefore, you should ensure to water your houseplants as recommended. Actually, it is okay to underwater the plant instead of overwatering it. Additionally, you should allow the soil to dry out before watering. This ensures that the soil does not dampen but stays well moist. Apart from causing mold and fungi, overwatering can also cause root rot. However, you can also water thoroughly, instead of shallow watering.

2. Repot The Soil

If you’ve tried out several remedies but they are not working, you can repot the soil. Yellow mold can be trouble and the best way to get rid of it completely is to repot. Get new, sterile soil and thoroughly clean the roots of the plant and the container before repotting. Avoid using hardwood-containing mulch or potting soil because that is what the mold feeds on.

Consider using cedar bark, pine bark, or pine straw. After repotting, make sure to maintain a conducive environment that will prohibit the development of mold and other fungi.

N/B: We have added a step-by-step guide below that you should follow if you want to repot your plant.

3. Use Natural Fungicide

One of the easiest ways to eradicate mold from your houseplant soil is by using a natural fungicide. Most of the natural ingredients are naturally antifungal, which means they can keep mold at bay. This includes baking soda, neem oil, cinnamon powder, and apple cider vinegar. Because baking soda has a high pH (the opposite of an acid), it can stop the growth of the yellow mold. Spray the mold with a water mixture made of 2 liters of water and 1 tablespoon of baking soda. It can be taken off the following day.

As for the vinegar, you can take a weak solution of apple cider vinegar and water. This should be sprayed on the soil and plant. Vinegar, like baking soda, harms the yellow mold due to its slightly different pH. (in this case, acidic). However, because vinegar is not a strong acid, it may be best to use it in its pure form (not in a water solution). Apply once more, and it should be dead ready for removal the next day.

While neem oil should be mixed with dish soap and water. This mixture should be sprayed on the soil to eradicate mold. Finally, you can also get rid of mold by sprinkling cinnamon on top of the soil.

4. Get Rid Of Debris

Another cause of the development of yellow mold is debris on top of the houseplant soil. If dead leaves and other debris are left to decay on top of the soil, they may give life to mold. This is because the dead leaves or matter on the houseplant soil decays and increases moisture levels. As a result, it forms desirable conditions for mold to grow and flourish.

Make it a routine to maintain your houseplant by removing any debris on top of the soil before watering. Also, don’t throw food or pour liquids on your houseplant’s soil. For instance, coffee is a type of fertilizer and it can trigger mold development.

5. Scraping It Off

The easiest and most basic way of removing mold from your houseplant soil is by scraping it off. Typically, mold grows less than 2-inches deep, which means that you can scrape it or scoop it out. You need to be very careful as the contaminated soil should not fall back. If you decide to undertake his method, follow up by cleaning the plant. Use a damp cloth to remove mold on the plant.

Afterward, use an antifungal to kill any remaining mold on the plant or soil.

6. Proper Lighting

If plants are kept healthy, they can resist diseases. Plants need light for photosynthesis, which is vital for their development. If your houseplant is not receiving enough light, you should change its position. Plants in dark or shady areas are susceptible to mold attack.

Sunlight helps your soil to dry out between watering and prevents mold from occurring. Therefore, if you’ve got a low-light indoor plant, you should be very careful with it. Ensure it is watered properly and the soil doesn’t dampen.

Leave the soil to dry before watering again.

Procedure For Repotting The Houseplant

The best way to get rid of mold on your houseplant or houseplant soil is by repotting. This gives you a new start with your plant. When you replace the contaminated soil, not only do you get rid of the mold but also prevent it from returning. To prevent transferring the mold to the new soil, you have to sterilize all the equipment you plan to utilize.

Below is the procedure for repotting your indoor plant:

Step 1: Grab a damp cloth and clear any yellow fuzz that’s on the plant stems or leaves.

Step 2: Cautiously remove the houseplant from the container and empty all the soil into another container or bag and throw it away.

Step 3: Take out all the dirt from the roots by placing them under running water. This will help to get rid of any mold on the roots.

Step 4: Examine the roots for any indication of diseases and prune using sterile shears. Do this cautiously to avoid damaging the roots.

Step 5: Get a sterile container and fill it one-third full with the right sterile potting soil.

Step 6: Insert the houseplant in the container and ensure it’s at the same growing height as before.

Step 7: Fill the container with the remaining sterile soil and thoroughly water. You will have to repeat watering after the topsoil has dried out. This helps to keep the soil moist as water will evaporate quickly.

Importance Of Repotting Houseplants

Repotting houseplants has many advantages aside from just eliminating yellow mold from your garden.

First of all, it allows the gardener to replace contaminated soil with fertile, nutrient-rich soil. This will boost your plant’s growth and development. Secondly, repotting helps to prevent the houseplant from becoming rootbound.

Additionally, repotting will allow you to examine the roots and find out if they are suffering from a disease or are healthy.


If you come across yellow mold or any other mold in your houseplant soil, there is nothing to panic about. Yellow mold is not dangerous to humans unless consumed. You can also get rid of this mold easily by following one of the methods that we’ve discussed above. But if you want to eradicate yellow mold, you should repot the plant, eliminating contaminated soil.

Besides, you should maintain a conducive environment for your plants to thrive so that they can resist the mold. With this detailed post, you no longer have to worry about yellow mold in your houseplant soil. This fungus can be eliminated quickly and easily.

You can now go ahead and protect your houseplant from yellow mold and other fungi!

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