Yellow mushroom in plant

What mushrooms popping up in lawns means


Question: Mushrooms have popped up all over my property in the past month. Are they a problem? How do I get rid/discourage them? What are the odds that they are poisonous?

Answer: Every year, autumn rainfall stimulates fungal mycelia, perennial underground masses of fungal threads, to start sending up their fruiting bodies, which we call mushrooms, toadstools, shelf fungus, conch, etc.

Most lawn mushrooms are a good sign that your soil is healthy below the soil surface. Fungi feed on decomposing plant material, breaking it down gradually through a process of feeding and digestion, eventually converting it into a material called humus. The fruiting bodies of mushrooms manufacture and send out microscopic spores that travel by air or water. Some grow into new mycelia, if the conditions are right.

Those mushrooms popping up on your property are most likely fertilizing your lawn, as fungi break down wood and other dead plant material into nutrients that other plants can use.

Many species of fungi are connected to your trees and shrubs and perennials via the roots as well in what scientists call “myccorhizal” relationships. The woody plants provide the mushrooms sugars, and the mushrooms allow minerals to be in a form available to the plants. Ninety-two percent of all plant families have relationships with fungi, via the roots. Our forest trees could not survive without their fungal myccorhizal partners.

Some fungi grow on live trees, such as honey mushrooms (Armillaria melea) and are considered plant pathogens, causing root rots, butt rot and other maladies. Others, including the shelf fungi (e.g. conchs), grow on dead trees and stumps and help break them down. Sometimes, mushrooms get introduced into a yard via bark chips or wood mulch brought in from another area.

So, basically, mushrooms or toadstools are an indication that soil building is going on in your lawn. This is a good thing.

Seeing fungi on living trees, on the other hand, may signal that your tree is sick or dying. A fungi will colonize a tree that is already injured or stressed by drought or insects. The tree may weaken and blow down more easily as the fungi break down and digest wood. So pay cautious attention to fruiting fungal bodies on your trees. If you see shelf fungus growing on a living tree in your yard, call an arborist for an evaluation.

If mushrooms and toadstools in your lawn offend you, remove them with a rake and throw them into the compost pile. But be ready to see a new crop spring up, as they can sprout new fruiting bodies in a day or so. After a while, the mushrooms will stop forming, and the mycelia will live unobtrusively in the soil for another year or more.

The vast majority of mushrooms are not poisonous. That said, I’ll also issue strict caution: Don’t let your children or pets eat lawn mushrooms, as some are poisonous or cause digestive upset. Lawn mushrooms also can uptake and contain toxins from the soil below.

Using fungicide chemicals to get rid of toadstools is wasteful and ineffective. Fungi live several feet below the soil surface.

Salem’s mushroom group, the Willamette Valley Mushroom Society, offers talks and outings during the mushroom season. On Dec. 2, Matt Trappe, author of “The Field Guide to North American Truffles,” will be presenting “The Mycelial Connection: How Fungi Manipulate Their Environment and Control Our Lives.” The talk will be at the Salem Public Library at 7 p.m. Admission is $5.

To learn more about this local group, check out their website at

Controlling Mushrooms

What are mushrooms?
Mushrooms are actually part of a fungus that grows underground, hidden from sight. The mushroom is the tip of a fungus iceberg, if you will – a clue that a large fungus lies buried in soil. Lawn fungi and their mushrooms don’t harm a lawn. They’re actually good guys in the ecosystem of your yard, breaking down organic material into nutrients your lawn can use.

A mushroom reproduces through spores, similar to seeds. The mushroom releases the spores, which spread by wind or water, to start a new fungal colony.

When most people hear the word “mushroom,” they think of the typical umbrella-shaped one, which is sometimes called a toadstool. But you might also spot other types of lawn fungus, including puffball, shaggy mane, Japanese parasol or the oddly-shaped and smelly stinkhorn.

When Mushrooms Occur
When mushrooms appear on the lawn, break them off or mow over them. If you have pets or children who might be tempted to taste mushrooms, gather the broken pieces and dispose of them.

Cause: Buried Organic Matter
A fungus grows by breaking down organic matter. In a lawn, that organic material could be buried timber, a stump, or tree or shrub roots that remain underground after plants have been removed.

Solution: In most cases, when the fungus has finished breaking down the buried organic matter, the fungus (and accompanying mushrooms) will disappear.

Cause: High Moisture
Periods of prolonged rain can coax mushrooms to form, as can overwatering a lawn. Heavily compacted soil and a thick thatch layer can create drainage problems, which provide ideal growing conditions for mushrooms.

Solution: While you can’t do much about overabundant rainfall, you can address lawn watering practices. Aim for deep, infrequent lawn watering, which encourages turf to develop an extensive root system. Learn tips for lawn irrigation. For drainage issues caused by compacted soil, try aerating your lawn. A thick layer of thatch in your lawn also could contribute to drainage issues.

Cause: Low light
While not all lawn mushrooms thrive in shady conditions, many do. If a corner of your yard offers high soil moisture combined with low light, mushrooms may appear.

Solution: Address the moisture issue using one of the techniques listed above. Next, if trees shade the lawn, tackle light tree trimming to allow more light to reach grass.

Should I be concerned about mushrooms in my lawn?

There appears to be wooden pieces within your lawn, is there a reason for that?

Does your lawn drain well?

Have you recently had a lot of rain fall?

Dead, rotting wood is an ideal material for mushrooms (fungus) to grow on/in, especially if that area also happens to be moist (damp).

Additionally, I believe your mushrooms in the lawn are directly related to this, Nothing will grow where tree was, or at least a byproduct…

From comments below: I think the wood pieces may be remnants from the mulch in the flowerbed nearby…or possibly from when they ground the stump in the tree that is also nearby. There’s not a lot of it in the lawn though.

  • If you follow the link given above, you will see that the tree stump and roots were left in the ground, therefore there’s “plenty” of dead, rotting wood under the lawn. As a general rule of thumb, a tree’s root system spreads out as far as the very edge of the tree’s canopy.

From comments below: There hasn’t been much rain since Oct 2010, in fact we’re in a drought. However, I water twice a day to keep my fescue from drying up and blowing away, so the ground is moist.

  • Watering a (Fescue) lawn twice a day isn’t necessary or recommended, and will in fact have a negative impact on the overall health of your lawn eg The grass will have a shallow root system (as the moisture is constantly at the surface of the soil), constant moisture is also a breeding ground for things like diseases and fungi…

  • Cool-season lawns require 1inch (25mm) of water a week to remain healthy & should be given in either one deep watering a week or two ½inch (12.5mm) waterings. More details can be found here.

I believe you’re seeing mushrooms in your lawn due to:

  • Removal of the tree (stump & roots were left in the ground), as I stated previously (refer to above “Additionally” comment).

  • Your twice daily lawn watering practices.

Those two conditions combined make an almost perfect mushroom growing environment (IMHO).

I have 2 white Mushrooms growing right out of the wall in the hall. Looks like they grew from somewhere inside to right through the plaster so we can see them when we are walking up the stairs in the hall. What product do you suggest?

Mushrooms growing inside the house is a sure sign of a current moisture problem. The first thing you should do is a good inspection of the house. You need to be looking the source of moisture. In all likelihood, it has something to do with the roof or the siding on the home. Additionally, it most likely is stemming from some upper-level area on the home. Small leaks can collect a lot of water from which mold, algae and fungi will grow.

Once the source of moisture is identified, any structural or mechanical problem should be corrected. Doing this first is paramount to solving the problem for good. Once corrected, the wood in this area and surrounding areas can be treated to prevent further fungi growth. Just “treating” without first fixing the leak or any damaged wood resulting from the leak would be a mistake. Regardless of the source of moisture, there are two products that will be well-suited for treating fungi growing in any type of structure.

As our online MOLD CONTROL ARTICLE explains, fungi growth can many times be found far away from the source of moisture. It’s not uncommon to see mushrooms growing in the basement which are deriving their moisture from a rooftop leak. In situations like this, the leak must first be fixed and then the roof must be treated to effectively kill the root of the fungi. I suspect this could be needed to resolve your problem. If the moisture source is from your roof or outside siding, the surface area should be sprayed with our MOLD AND ALGAE KILLER.

Since mold and fungi will take root on most any surface the area between the leak and the mushroom growth needs to be well inspected to first ensure there is no structural damage to the home. Molds and fungi literally eat the wood on which they live. Though slow, this consumption will alter and ultimately weaken structural members like floor joists, rafters and sill plates. Make sure all structural members of the home are intact and have not sustained measurable damage. In most situations like you’ve described, once the leak has been repaired the structural members in the attic and walls should be treated to ensure no further growth can be sustained. The best product for any wood or cellulose material in the home would be BORACARE or the new BORACARE MOLDCARE combination. Boracare by itself will penetrate wood and protect it from insect infestation as well as most common fungi. However, given the current status of fungi growth in your home, I would recommend the Boracare along with some Moldcare. By adding the Moldcare to the tank mix, you’re taking the extra measure needed to ensure mold and fungi cannot return to where they once prospered. This extra protection is many times needed when treating structural members. This is especially true when treating in the home and the source of moisture is not easy to identify or repair.

If you find the fungi is also growing on surfaces other than wood, these areas should first be treated with MOLD BLASTER and then MOLD BLOCK. Mole Blaster can be used on any surfaces and does a good job of killing active mold, algae and fungi that many times is not visible to the naked eye. Mold Blocker, does a great job of preventing future growth of mold and fungi for up to one year following the treatment.

The outside Mold Algae Killer comes in a “ready to spray” hose end type applicator and does not require any special equipment. Boracare, Mold Blaster, and Moldblock all need to be applied with a good PUMP SPRAYER. When treating above living area spaces, be sure to apply the material heavy enough to get a uniform treatment but not so heavy that it puddles and leaks through the ceiling into living spaces. When treating attic areas it will many times be smarter to do two or three “light” applications instead of one heavy one to avoid leaking it down. If you are not able to direct spray material into wall voids from above, the use of a FOAMING TOOL may be needed. This tool will enable you to get products like Boracare into wall voids where mold and fungi live. Based on where you’re seeing the mushroom at your house, I suspect you’ll be needing to treat some wall voids to get long term control.

Mold and fungi growth in the home is a sure sign of moisture problems. Correcting the problem is critical if you wish to protect the long-term health and stability of the structure. Once this problem has been identified and corrected, a good treatment with the products listed above will both kill and prevent future mold or algae growth. If you have further questions regarding the treatment process, please give us a call on our toll-free 1 –800 — 877 — 7290.

When mushrooms start growing inside your home it is a little hard to argue you were not aware of the moisture problem.

The real risk

Mould and fungi will take root on almost any surface when there is moisture and a food source present. Mushrooms are fungi that require oxygen, a food source, suitable temperature and a source of water to thrive.

While fungal spores that generate mushrooms are microscopic and light enough to be carried by the wind, on clothing or on shoes, for a mushroom to grow two of the single cell spores must combine.

Mushrooms generally require high humidity and low light to grow. Therefore when mushrooms such as the ones shown above are located, the substrate needs to be carefully inspected for structural damage as it is an indicator of high levels of moisture being present over an extended period of time.

The real danger of mushrooms growing inside the house is they are a sign of a significant moisture problem that could support the more harmful growth of black mould.

Treating the risk

By simply having fresh air and sunlight in the home, humidity is reduced and the surface is able to dry naturally if there is a source of moisture present.

Without these elements fungi can thrive and while mushrooms in bathrooms and basements are more common because of these reasons, mushrooms growing out of carpet is a big red flag!

Simply treating the mushrooms with a fungicide in this situation is not enough to prevent future fungal problems. Rather, like all moulds and fungi, the cause of the moisture must be identified, treated and the moisture removed,before the area is treated.


In this instance the source of the moisture was from several sources. Missing grout in the shower cubicle, lack of sealant around the tap spindles to provide a waterproof seal, a leaking pipe in the wall and a failure in the laundry taps. All of these elements combined to provide sufficient moisture to support the growth of the mushrooms inside the house.

“Ink cap mushrooms are very distinctive because they don’t last long. The strange thing about them is they autodeliquesce, which means they digest themselves – they basically disintegrate into a black ink.”

The mushrooms are normally seen growing outside on mulch or soil. Spotting them growing indoors is a sign of some seriously soggy wood.

The fungus has been identified as an ink cap mushroom, which digests itself, leaving a black slime. Photo/Supplied

“This is not an invasive fungus like dry rot but rather a symptom of an underlying weather-tightness or leaking plumbing problem,” he said.

“They’re doing quite a useful thing in a way, indicating there’s a big problem in the wall. When you see paint blistering and touch the paint and it feels soft behind, there are absolutely going to be fungi growing but they’re not the cause of the problem – they’re the symptom.”

People – especially children – should not be living in a house with walls damp enough to grow mushrooms, he said.

The wood would likely need to be completely replaced, he added.


#072: Leucocooprinus birnbaumii, The Yellow Houseplant Mushroom

This small, yellow, parasol mushroom is a tropical species but can be found throughout the world in greenhouses and indoors among potted plants. These mushrooms often surprise people by appearing suddenly indoors at any time of the year. birnbaumii is a mostly harmless mushroom. It does not damage your plants at all, but it should not be eaten. The Yellow Houseplant Mushroom is mildly poisonous, but symptoms appear only when it is eaten in large quantities. If you are worried that a pet or child may eat the mushrooms, then you may want to pick the mushrooms and throw them out. This will not get rid of the fungus, so you will have to check the pot regularly. The mushrooms may also spread to other pots in your house through airborne spores. If you want to get rid of them forever, then you will probably have to throw away your houseplant. For those of you not concerned about accidental ingestion, feel free to enjoy the extra splash of color that the Yellow Houseplant Mushroom brings to your room!*

The young fruiting bodies of L. birnbaumii start out as little more than tiny, yellow ovals protruding from the soil. As the mushroom grows, the stalk elongates and gets bigger. The cap also grows in size, but remains oval-shaped. At this intermediate stage, the mushroom looks kind of like a small, yellow, fuzzy microphone. This microphone shape is frequently somewhat distorted because the base is usually expanded and there is often an extra bump at the top of the oval pileus. The entire mushroom is colored yellow and covered with tiny, yellow scales. As the mushroom matures, the bottom of the cap separates from the stipe and expands like an umbrella being opened. A small, fragile ring is left on the stipe where the edge of the cap was, but this frequently disappears soon after the cap begins expainding. The fully-grown pileus will be broadly conical to bell-shaped. At this stage, the pileus begins to lose some of its color. The edge of the cap becomes yellowish white to pale yellow and the rest of the cap darkens toward the center. No scales are added to the pileus once it starts expanding, so the yellow scales become spread out (except for those over the center), diluting the color further. Underneath the pileus, the mushroom sports pale yellow gills that are free from the stipe. The gills give a white spore print. Even fully grown, these mushrooms are not very big. They are 3-10cm (1.2-4in) tall and 2.5-6cm (1-2.4in) wide. Despite this, these brightly-colored mushrooms are almost impossible to miss when they are growing indoors.

L. birnbaumii is saprobic and feeds on dead plant material. This means that it does not harm your potted plants. Actually, it helps release nutrients back into the soil, which is beneficial to your plants. In temperate regions, the Yellow Houseplant Mushroom is usually spread through infected soil. If you find these mushrooms growing in your house, they either came from the greenhouse that grew your plant or came with the soil you added to your potted plant. Although greenhouses and soil companies try to exclude mushrooms like L. birnbaumii from their products, there are occasionally some intrepid individuals sneak through. People can carry the spores from one greenhouse to another, making eradication of this mushroom a difficult problem to tackle. The Yellow Houseplant Mushroom is most commonly encountered indoors, but it can occasionally be found outdoors. In temperate North America, it prefers to fruit in the summer from cultivated areas like gardens. It can sometimes be found growing in forests, usually near disturbed ground.

L. birnbaumii belongs to the phylum Basidiomycota, class Agaricomycetes, order Agaricales, and family Agaricaceae. A more familiar member of this taxonomic family is Agaricus bisporus, which can be found in a number of varieties at your local grocery store (see FFF#002 for more on A. bisporus). The species name birnbaumii pays tribute to a German garden inspector named Birnbaum who found the mushrooms growing alongside pineapples in a noble’s garden in 1839. There are many different common names for this fungus, but most are variations of “Yellow Houseplant Mushroom,” which is the name most often used in the United States. In the United Kingdom, however, the preferred common name is “the Plantpot Dapperling.”

* Note: growing lots of mushrooms indoors can result in breathing problems. A high concentration of airborne spores will cause symptoms similar to smoke inhalation. For this reason, you should not cultivate mushrooms indoors. That being said, a few mushrooms growing alongside a houseplant will probably not produce enough spores to cause any problems. People who experience symptoms usually either are growing large quantities of oyster mushrooms in their home or are working in the mushroom industry and not following proper safety procedures.

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