Yellow Fungus on Soil | Mold or Fungus and Is It Harmful?

It’s frustrating when you spend time and effort on nurturing plants & making sure all the conditions are right, only to discover a rather unsavory residue on the surface of the soil. Whether you’ve spent the spring nursing your tomatoes into beautiful bursting fruits or you’ve had indoor houseplants that have been a mainstay in your home for years, it can be startling to encounter yellow fungus on soil that you so lovingly care for.

It might get you wondering—will the fungus kill my plants? Is the soil unusable because of it?

I asked these questions myself when I found yellow moldy-looking fungus in my potting medium and in my garden. Luckily, between research and trial and error, I have the answers you need to help you differentiate between yellow-colored mold and fungus, whether it can pose a risk, and how to get rid of it.

Identifying Yellow Fungus or Mold on Soil

Not all of this yellow furry substance that you find on your soil is the same. Here’s a look at the most common types:

Fungus or Mold?

If you’ve used the words fungus and mold interchangeably, I get it—many people do. The good news is that you’re not entirely mistaken since mold falls under the broader fungus classification.

Fungus is a kingdom, so scientists classify several species in this category, including:

• Mold
• Yeast
• Mildew
• Mushrooms

Whereas we all know that species in the fungus kingdom such as mushrooms are easy to spot with the naked eye, this isn’t always the case with mold. 

Individual mold spores measure a mere 2 – 10 microns in size. So, it takes many mold spores growing close together to make them visible in your soil.

The bottom line?

If you have a mold problem, it’s the same as saying you have a fungus problem. But if you have a fungus problem, it may not be from mold.

Yellow Mushrooms

Many species of yellow mushrooms exist, varying in shape and size. Their colors vary enormously, ranging from bright yellowy orange to pale yellow or even a deep gold color.

Some of the most common species of yellow mushrooms include:

• Golden oyster mushroom
• Flowerpot parasol
• Jack-O-Lantern mushroom
• Chicken of the woods

Some yellow mushrooms grow individually, with classic mushroom tops. Others grow in clusters, forming large masses on tree bark or in mulch. It’s also very common to see mushrooms growing on your lawn and these can be easy to deal with and remove.

Yellow mushrooms growing in your soil, however, means that there are invisible spores present. The good news is they won’t harm your plants. Indeed, they can help condition soil which is later absorbed by your plants as valuable nutrients.

Yellow Slime Mold

It’s common for dog owners to believe that their dogs vomited when they first lay their eyes on yellow slime mold. I know that’s an unappealing visual, but it’s among the best ways to describe it—the mold has a foamy texture and loves to cling to grass.

If you encounter yellow slime mold at a later stage in its life cycle, you may find it in a crusty state just like in the picture above. At that point, it’s trying to disperse its spores ready for the next time you mow or rake your lawn.

It’s easy to tell the difference as yellow egg balls from insects tend to be clumped together and look slimy. The shells or remains of fertilizer granules will be more evenly dispersed in the soil and dull in color.

To know for sure, it’s worth squeezing one of the balls between your thumb and finger to see what happens. If it is easy to squish, it’s likely the egg of an insect, but if it breaks into lumps or is powdery, then chances are its fertilizer. Always be sure to wash your hands thoroughly afterward.

Yellow Fungus Growing Gardens

There are many reasons that yellow fungus grows in gardens, but the following factors typically come into play:

• Wet environment
• Rotting plants
• Not a lot of sunlight
• Lack of aeration
• Presence of fungus spores
• Poor quality fertilizer

Rotting plant material is food for fungi since its purpose in the life cycle is to break down dead organisms to promote new growth.

Some parts of the world naturally have more fungi than others. For example, if you live in dry, sunny Arizona it’s uncommon to encounter fungus in your garden compared to if you live in the northeast.

Although nature plays a big role in determining whether fungus grows in your garden, you do have some control over the situation. For example, you may be unintentionally promoting fungus growth if you overwater your plants.

Furthermore, if you struggle with yellow fungus growing on your indoor potted plants, it could be because you don’t have them in an area that receives enough sunlight. There’s no shortage of studies showing that sunlight is detrimental to fungus growth because of UV rays that can damage its cells.

Mulch is another reason that yellow fungus is suddenly showing up in your garden when you never used to have that issue. Part of the reason could be that the mulch contained yellow fungus spores. The other part is that mulch is an ideal host for this fungus.

Yellow Houseplant Mushroom in my Pots

Yellow houseplant mushrooms go by several names, including yellow parasol and flowerpot parasol. However, its scientific name is Leucocoprinus birnbaumii. 

The reason why yellow houseplant mushrooms gravitate towards potted plants is that they love to feed on the decaying matter in potting soil. Inexperienced gardeners also tend to overwater their plants out of love, which can spark this mushroom growth.

Furthermore, potted plants tend to struggle with proper drainage. You likely know that you need to keep your plants in a pot with holes in the bottom. However, if you water them so much that liquid ends up pooling at the base of those holes, you’re creating an environment that welcomes yellow houseplant mushrooms.

It’s understandable to assume that yellow houseplant mushrooms are poisonous to touch given their bright yellow color. But that’s only partially true—they won’t harm your plants, and you can pick them with your bare hands without negative side effects. Unlike many lawn mushrooms, they are not poisonous to touch.

However, they’re dangerous for people and animals to ingest. Therefore, if you notice yellow houseplant mushrooms growing inside your home, it’s best to carefully remove them, especially if you have young children or pets.

How Long Does Yellow Fungus Live in Soil?

Once fungus spores arrive in your soil, the fungus will remain for as long as the conditions allow it. So, if your soil is moist, has lots of decaying organic matter, has little access to sun, and is in fairly warm conditions, you can expect to frequently fight with this fungus.

It’s typically easier to remove yellow mushrooms from your soil than yellow slime mold. When physically removing these funguses, you should also be aware of what life cycle stage they’re at; if they’re moist, there’s less of a chance that you’ll spread their spores as you remove them than when they’re dry.

Yellow fungus tends to have a quick lifecycle, which contributes to its rapid spread. Young yellow fungus has a moist and slimy texture (if you have a case of yellow slime mold). 

As the fungus matures, it becomes dried out. By doing so, the fungus is more easily able to spread its pores, often helped by a windy day. 

Is Yellow Fungus in Soil Harmful

Yellow fungus isn’t harmful to your soil. In fact, it can help your plants stay healthy.

In the case of yellow mushrooms, the mushrooms eat dead insects, decaying organic matter, and dead plant roots. They then process this food and excrete it back into the soil by means of providing usable nutrients.

On the other hand, yellow slime mold thrives off eating bad bacteria and pathogens that may otherwise kill your plants.

Needless to say, yellow fungus is a lot more damaging to the human eye than it is to your garden or potted plants.

How to Get Rid of Yellow Fungus in Soil

There are several strategies you can use for getting rid of yellow fungus on the soil. One of the most common is for people to physically remove the fungus.

Doing so is an excellent option if you don’t mind the fungus but want your garden or potted plants looking in tip-top shape before you have company over. However, manually extracting any type of fungus tends to be a lot of work for little reward.

That’s because you aren’t taking care of the “root” of the problem—the fact is fungus spores are scattered throughout your soil. So, if you have potted plants, a more effective technique is to relocate your plants to new potting soil.

Although fungus shouldn’t cause physical harm to your skin if you touch it, it’s best to wear gloves and even a mask. Some people have fungus sensitivities, so that’ll help you avoid the discomfort from potential respiratory issues after handling the fungus.

Repotting your plants takes time. So, another option is to use a natural antifungal to tackle the problem, which I’ll talk about next.

Regardless of the removal method you choose, once you get rid of it from your soil, it’s equally important to prevent it from returning. I recommend keeping decaying organic material (such as dead leaves) from congregating around your plants, making sure they have access to plenty of sunlight and don’t overwater them.

Natural Antifungals for Soil

There’s no need to muck up the environment and your veggies with harsh chemicals when trying to get rid of fungus. Instead, below are three amazing natural antifungal strategies.

1. Baking soda
2. Cooking oil
3. Dishwashing soap

You could theoretically mix these items together as an anti-fungus solution. But in reality, just one of them will do, mixed with some water if you’re using baking soda or dishwashing soap.

If you choose to go with the baking soda route, I recommend mixing one teaspoon of baking soda per one liter of water. On the other hand, you can give dishwashing soap a single squeeze and mix it in with about the same amount of water.

Oil won’t mix well in water. So, you can spray some directly onto the soil, which will make it challenging for fungus spores to cling to.

Before using these natural antifungal solutions, there are a few things you should be mindful of:

• Use a plain dishwashing soap without bleach, degreaser, or other harsh additives.
• Test the solution on a small portion of your soil first and give it some time to see how your plant reacts.
• Avoid applying the solution on a sunny day, since it may burn your plants.

Using Vinegar an Antifungal

Vinegar is a powerful antifungal, but you shouldn’t use it on your plants. The reason being is that vinegar has a high acidity level, making it deadly to many plants.

That said, a handful of plants do well in an acidic environment. They include:

• Gardenias
• Hydrangeas
• Rhododendrons

So, if you encounter yellow fungi growing on any of these plant species, it might be worth giving vinegar a try. Just make sure to dilute it with water first and test it out on a small patch of your garden before dousing all your soil in vinegar.

Final Thoughts

Yellow fungus on your soil isn’t something to panic over in terms of the health of your plant, but there’s nothing wrong with wanting it gone—especially if you have pets or young kids. 

By using the fungus removal strategies I described here, you’ll soon get to enjoy a garden full of green plants and soil without an offensive yellow hue.

FAQs Yellow Fungi on Soil

If you still have questions about finding yellow-colored fungus in your soil, we’re here to help.