Yellow Mushrooms: Why They Appear and What to Do (2024 Guide)

Do you have little yellow mushrooms popping up in your pot plants? As a pot plant enthusiast, or anyone with a plant or two in your home, you may not be thinking about growing mushrooms while you arrange your plants in just the right spot. So, it may come as a bit of surprise when you glimpse yellow mushrooms popping up in the potting soil!

In this guide, we answer the following questions and more:

• What are they?
• Why are they here?
• Where did they come from?
• How do I deal with them?

Firstly, let me assure you, they are doing more good than harm, so you can relax while you read this guide. No harm will come to your plant and, provided no-one eats them, the little yellow mushrooms will not harm your family or your pets.

Let’s take a look at what they are, and then you can decide what you want to do about them after you’ve read all the information we have for you:

What are those Yellow Mushrooms?

Simply put, they are yellow houseplant mushrooms (Leucocoprinus birnbaumii), also known as flowerpot parasols or plant pot dapperlings. They are a species of gilled mushroom in the family Agaricaceae. Yellow houseplant mushrooms are common in the tropics and subtropics, and are also sometimes found in greenhouses and flowerpots in temperate regions.

These vibrant fungi are prized not only for their aesthetic appeal but also for their intriguing biology. Yellow houseplant mushrooms have a fascinating symbiotic relationship with certain plants, particularly those grown in potting soil. Their presence in flowerpots can indicate healthy soil conditions, as they help to break down organic matter and facilitate nutrient cycling.

Furthermore, their appearance serves as a reminder of the interconnectedness of ecosystems, highlighting the role of fungi in supporting plant health and vitality. While their striking yellow hue may catch the eye, their ecological significance extends far beyond mere visual delight.

Take a look at this video:

How to Identify Leucocoprinus birnbaumii

Indoor identification of the Yellow Houseplant mushroom is really easy. If there are small yellow mushrooms growing alongside your houseplants, they are probably Leucocoprinus birnbaumii, or simply, yellow mushrooms.

To be one hundred percent sure, you can identify them by looking for the following characteristics:

• Pale to bright yellow throughout, including the inner flesh
• The mushroom cap is one to two inches tall. It starts out oval in shape and becomes bell-shaped as it matures.
• The cap is textured with dots or scales that are the same shade of yellow as the rest of the mushroom.
• It is a gilled mushroom, but the gills do not attach to the stem.
• The stipe (stalk) has a ring around it that usually disappears as the fungi mature. The ring is a remnant of a veil that protects the gills while they are developing.
• The stipe is a few inches tall.
• The spore print is white.
• They thrive in hot weather and wet soil.

Yellow mushrooms are saprotrophic, which means that they not parasitic, feed on dead organic material and, therefore, won’t hurt a healthy houseplant.

Now that we know what they are, let’s find out what they are doing in your potting soil:

Why Do I Have Yellow Mushrooms in My Houseplants, and What do They do?

This is a two-fold question, so let’s look at the WHY first, and then the WHAT:

Why are they there?

The mushrooms in your potted plants could be there because of contaminated potting soil. Mushroom spores are not visible, so it’s impossible to pick them out during potting soil processing, but once the spores are in, they are quickly and easily distributed when the soil is packaged and dispatched.

The spores can make their way into the soil via a contaminated ingredient at a farm or factory or even from the clothing of the people who work with the product.

If you have mushrooms in your potting soil, it could be for any one of these reasons:

1. There were spores present in the soil when you bought it.
2. Mushroom spores blew in or were carried in from a nearby plant.
3. Your plant had some of the spores on it when you bought it.
4. The potting soil is nice and rich. Mushrooms thrive in rich soil.
5. Your soil is too wet. Make sure you are not overwatering your plants and they’re not in too much humidity. However, if this is the case, the plant would be showing other signs of overwatering like limp leaves, poor condition, or root rot.

A Little Note on Yellow Mushrooms, Root Rot and Repotting: If you see any signs of root rot, and you have mushrooms, you can remove the plant from the soil, clip away mushy roots and rise the root system off in clean water. Then repot the plant in a clean pot, using new growing medium. An organic potting mix, amended with some perlite for good drainage and a little organic compost or worm castings will work very well for most indoor plants.

Use water that is room temperature to avoid shocking the plant too much and take care to wash your hands, ideally with an environmentally friendly soap, and clean and sterilize all your implements before you repot to avoid any contamination with bacteria or spores. Dispose of the old potting mix away from your other plants. This will work well for the root rot, but it may not completely eradicate your Yellow Mushrooms because some spores may remain and re-grow.

What do they do?

Please note: they will not harm your house plant.
On the contrary, they are helping your houseplant. Mushrooms are a sign of healthy soil, and they improve the quality of your soil.

Unfortunately, when people see mushrooms indoors, they associate them with unwanted fungus, like mold. This association is not fair on mushrooms at all! Mold is a fungus, yes, but it is a parasite. Mushrooms are also a fungus, but they either help put nutrients back into the earth or help plants exchange nutrients.

Finding mushrooms in your house plants is not a horrible thing (unless it is a sign of overwatering).

Now that you know what the yellow mushrooms do, you can decide what you are going to do about them:

What Should I Do with the Yellow Mushrooms in My Potted Plants?

If there is no danger of anyone eating them, I would recommend that you leave them. After all, they are quite attractive little things, and having them in your pot plants may be an interesting topic of conversation when people come to visit.

If, however, you choose to get rid of them, you have several courses of action to choose from:

1. The easiest thing to do, but also the most extreme, is to get rid of the pot with its plant and soil completely. Either move it outside or throw it away.
2. The most complicated and risky course of action would be to change the soil. Removing all the soil from the plant’s roots may cause the plant to go into shock. There is also no guarantee that you will get rid of all the spores, and after all this effort, the mushrooms may appear again.
   Removing and replacing several inches of topsoil is less drastic but doesn’t guarantee that you will have removed all the spores.
3. A less aggressive, ongoing, plan would be to remove the mushrooms as they pop up, thus eliminating any chance of them re-sporing – unless the spores are being carried in from another source.
4. Using a fungicide is another action that may not result in a favorable outcome as it is also not guaranteed to work. Not only is working with fungicides unpleasant as they can cause minor allergic reactions but when you read all about fungicides, you have to wonder if the chemicals used in them are not perhaps more harmful than the fungi themselves. If you would like some organic gardening tips, you can read this guide.
5. You could try changing the conditions that the plant is kept in – cooler temperature, less humidity, dryer soil, more airflow. This may reduce the abundance of mushrooms. Unfortunately, it may also have a negative impact on your plant because the conditions that most pot plants enjoy are the same conditions that mushrooms grow in.

Truth be told, yellow mushrooms are very difficult to get rid of because the mycelium and the spores have probably settled deep within your plant’s roots and potting soil. It may be almost impossible to remove them entirely.

 

Will Sterilizing the Potting Soil Prevent Fungi in Pot Plants?

One way to make sure you won’t have yellow mushrooms or any other fungi or weeds sprouting up in your potted plants would be to sterilize the soil you use.

The most effective way to sterilize small amounts of soil is by steaming, or you can use a microwave or an oven. The soil needs to reach a temperature of  180° F (82° C.) Larger quantities of soil can be sterilized using solarization.

Solarization uses the free energy provided by the sun to heat up and thus sterilize the soil. You can use clear plastic or black plastic. Solar energy is free and renewable – have a look at this article if you’re looking for solar water heating solutions.

Step by Step Guide to Solarize Soil:

1. Remove debris and break up large clods.
2. Wet the soil thoroughly.
3. Fill clear plastic bags with soil. In cooler climates, use black plastic bags as this helps hold more heat. Alternatively, cover heaps of soil with plastic sheeting that is anchored down snugly. Make sure your plastic-covered soil is in a place where it will receive the maximum hours of sunlight.
4. Leave the soil for four to six weeks. Not only will this process rid the soil of any pests, weeds, unwanted seeds, and fungi spores, but it will also break down plant matter, increasing the nutrient value of the soil.

In Conclusion

Unless they pose a threat to the human inhabitants or the pets in your home, we think you should make peace with the yellow mushrooms in your potted plants. They are not harming your plant, and, in fact, they are a sign that your plant is growing in good soil and the right conditions.

References

https://www.house-plant-hobbyist.com/blog/2019/11/15/mushrooms-in-your-houseplants-why-they-are-a-good-sign

https://www.mushroom-appreciation.com/yellow-mushrooms.html#sthash.K8SuQmnl.dpbs

https://planethouseplant.com/why-are-there-mushrooms-growing-on-my-house-plant/

https://morningchores.com/how-to-sterilize-soil/