If you’re like most gardeners, the sudden appearance of mushrooms growing among your flowers or vegetables is a very unwelcome sight. But I don’t think you should panic quite yet!
Despite their somewhat lackluster reputation, mushrooms are more often beneficial to the garden ecosystem than they are harmful. Unfortunately, it’s the few ‘bad apples’ that earn all mushroom-bearing fungi a bad name.
Instead of treating all garden mushrooms as dangerous invaders, I encourage you to learn a bit about how these fungal structures benefit the soil and support plant health overall. I’ve covered everything you need to know to get started below, as well as some expert tips for identifying and handling the less savory mushrooms growing in your garden.
- What Causes Mushrooms To Grow In Your Garden?
- Are Garden Mushrooms Beneficial?
- Are Garden Mushrooms Harmful?
- Should You Remove Mushrooms from Vegetable Beds?
- Will Mushrooms Grow Among Flower Beds?
- Will Mushrooms Growing on Trees Spread?
- How To Stop Garden Mushrooms from Growing
- FAQs Mushrooms Growing In Garden
What Causes Mushrooms To Grow In Your Garden?
Fungi will grow wherever and whenever the conditions are right. It just so happens that some mushroom species prefer the environment of a yard or garden to that of, say, the forest floor. In that sense, mushrooms are very similar to weedy plants.
The real question is why mushrooms tend to grow in some gardens but not others. Or why you can go years without mushroom activity in your beds only to have a sudden flush of growth one season.
In order for mushrooms to emerge from the soil, a few key factors must align. Some of these factors can be controlled. Others are entirely up to Mother Nature.
If mushrooms have recently appeared in your garden, then it’s safe to say that some or all of the factors below are at play:
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Mushroom Spores in Soil or on the Wind
According to the University of New Hampshire, many garden mushrooms emerge from pre-existing fungi living beneath the soil’s surface. Still, those fungi have to come from somewhere.
Mushroom-creating fungi are frequently spread via the soil. If you add soil to your garden that contains fungus spores, those spores will likely grow and eventually put out mushrooms. This process is no different than using soil containing weed seeds that then sprout and invade your garden.
Spores can be spread in both natural and bagged soil. If you’ve had a recent mushroom outbreak in part of your garden, be careful taking soil from that area to redistribute elsewhere.
Like plant seeds, fungus spores can also spread in the wind. However, these spores are so small that they rarely travel further than several inches from the originating fungus.
Note that fungus spores can remain hidden in the soil for quite some time before ever forming mushrooms. While this may be the first time you’ve seen mushrooms in your garden, there’s no way to know how long the fungus itself has been living in the soil.
Warm and Humid Weather
Mushrooms thrive in warm — not hot — weather, especially when there is plenty of moisture in the air. On average, mushrooms prefer temperatures around 60°F but will grow in conditions slightly warmer and cooler. You’ll often notice a flush of mushrooms appear when the day- and night-time temperatures stay near this range.
Humidity triggers mushroom production because it adds moisture to the environment. When the air is humid, damp soil from rain or sprinklers will not dry out as quickly. This gives mushrooms time to grow before the conditions change once again.
Damp Rich Organic Matter
Natural soil gets its nutrients from decaying organic matter from plants and animals. While these materials are responsible for releasing vital nutrients like nitrogen into the ground, they are also the preferred food source of mushrooms and other fungi.
Make no mistake — organic matter is extremely beneficial to garden soil. You should not avoid aged compost and other amendments in an effort to keep fungi out of your garden beds. But do keep in mind that excess organic matter can encourage fungal growth.
Are Garden Mushrooms Beneficial?
Whether or not you see mushrooms as beneficial to your garden is largely about perspective. But there’s no reason for these fungi to be demonized to the extent they often are within the gardening community.
Many fungi species maintain symbiotic relationships with plants. These fungi aid plant roots in accessing resources like water and nutrients. According to Oregon State University, fungi may help keep soil-borne plant diseases at bay. These benefits come from the fungal structures beneath the soil’s surface — not the mushrooms themselves — but the two are, more or less, inextricable.
More often than not, the reason mushrooms are unwanted in garden beds is that they are seen as ugly. (I think a few mushrooms can be a charming addition to a garden. But that’s just my personal opinion.)
Another reason so many gardeners view mushrooms as a plague rather than a boon is that they often appear when conditions aren’t ideal for regular plant life. For example, the appearance of mushrooms growing in a potted plant is a clear sign that the container lacks adequate drainage.
If there’s one nugget of information I leave you with, I hope it’s that mushrooms are an indicator of potential problems rather than a problem in and of themselves. At the end of the day, mushrooms are as valid a part of the garden ecosystem as flowers, trees, or grass.
Are Mushrooms Good for Soil?
Mushrooms aren’t always appreciated within the cultivated garden. However, there’s no denying the importance of mushrooms to the soil as a whole.
Mushrooms are a vital facet of the decomposition process. Mushroom-creating fungi help break down decaying plant and animal matter, releasing valuable nutrients into the soil. Without fungi (not to mention a number of insects, bacteria, and other organisms), fertile soil would cease to exist in nature.
Are Garden Mushrooms Harmful?
It’s common knowledge that you should never ingest an unidentified mushroom found in your garden or otherwise. However, it’s safe to say that the vast majority of mushroom species are relatively harmless to humans and animals.
According to Medscape, there are approximately 100 mushrooms known to cause illness in humans. Even fewer are potentially lethal when ingested.
That might sound like a lot but there are literally thousands of different mushroom varieties in the world. While there is a chance that a poisonous mushroom could decide to call your lawn or garden home, it is an extremely slim one.
Also, it’s important to keep in mind that nearly all mushroom toxicity cases are the result of misidentification when foraging. As long as you don’t try to eat the mushrooms growing in your garden, even poisonous varieties are fairly harmless.
Though garden mushrooms are rarely poisonous, you should still take the time to identify the fungi living on your property. This is especially important if you have young children or pets who may not know better than to touch or ingest found mushrooms.
Can You Touch Garden Mushrooms?
Rest assured, you won’t be harmed by simply touching a mushroom. Even highly poisonous mushrooms are safe to handle within reason.
That doesn’t mean I recommend throwing caution to the wind altogether when dealing with such specimens. For example, you don’t want to touch a poisonous mushroom and then accidentally touch your mouth, nose, or eyes.
Personally, I prefer to handle all mushrooms with basic garden gloves. This allows for easier cleanup and provides a better grip when removing large specimens. It has little to do with the safety of touching garden mushrooms but donning a thick pair of gloves may help you feel more confident in doing so.
If you have positively identified a poisonous mushroom in your garden, you may want to dedicate a pair of single-use gloves to the chore. Alternatively, I recommend washing your gloves immediately after handling potentially toxic mushrooms. These extra precautions are more than adequate for handling poisonous mushrooms — it’s always better to be safe than sorry.
Types of Poisonous Mushrooms
There is little overlap between the mushrooms most commonly found in lawns and gardens and those that are poisonous to people. However, these five species are worth familiarizing yourself with in case they show up in your yard:
False Parasol Mushroom
False parasol mushrooms are commonly ingested throughout North America both because they closely resemble an edible species of mushroom and because they frequently grow in lawns and gardens.
Common symptoms include vomiting and stomach upset.
Conocybe filaris is a potentially lethal mushroom that affects the liver when ingested.
This tall, brown mushroom is most commonly found in residential lawns and compost piles.
The yellow-staining mushroom, or Agaricus xanthodermus, is easily identified by the yellow discoloration that appears where the fungus is damaged or cut.
Eating this mushroom typically causes stomach upset.
Inky cap mushroom
Inky cap mushrooms are technically edible but proceed with caution.
Consuming alcohol within days of eating this mushroom will trigger symptoms like stomach upset, heart irregularities, and tingling extremities.
Common earthball mushroom
Common earthball mushrooms are frequently eaten because they resemble edible puffball mushrooms.
These mushrooms grow in many areas, including lawns and garden beds.
Should You Remove Mushrooms from Vegetable Beds?
Except in rare cases where poisonous mushrooms are found, there’s little reason to remove mushrooms from a vegetable bed. Even if you do remove the mushrooms growing out of the soil, the fungus responsible for them will continue to thrive under the surface.
Mushrooms are quite common in vegetable beds. This is because vegetable plants prefer rich soil that is extremely high in organic matter. You might find mushrooms growing in in-ground beds, raised containers, and small pots.
Many gardeners worry that mushrooms will harm or contaminate their vegetable crops similarly to mold. However, mushrooms only grow in decaying organic matter. As long as your vegetables are alive, they will be perfectly safe.
Unless your vegetable garden is placed front and center in your landscape, aesthetics probably aren’t at the top of your priority list. The only potential benefit to removing mushrooms from a vegetable garden is preventing the further spread of fungal spores.
Will Mushrooms Grow Among Flower Beds?
Mushrooms may appear in flower beds containing adequate moisture and organic matter. In my experience, you’re more likely to encounter mushrooms in shaded areas of your garden.
In some climates, it’s possible to cultivate specific mushrooms outdoors. This practice is usually done with safe, edible mushrooms — similar to growing culinary herbs in the garden. It is rarely done for the visual appeal of the mushrooms being grown.
Unfortunately, you can’t plant mushrooms in the soil among your flowers and expect much success. Instead, cultivating mushrooms on purpose requires using cut wood or similar material as a growing medium.
Will Mushrooms Growing on Trees Spread?
When mushrooms start growing on a living tree, it is almost always a sign that the tree’s interior has started to rot. Unfortunately, there is rarely anything that can be done to save the tree by the time mushrooms appear. The fungus the mushrooms belong to has already started decaying the wood inside.
Removing the mushrooms will not actually get rid of the fungus. The main fungal organism is inside the tree. However, removing the mushrooms can prevent fungal spores from traveling to nearby surfaces, including other trees or your garden beds.
How To Stop Garden Mushrooms from Growing
Mushrooms only grow when the conditions are right. Most mushrooms need high moisture and lots of organic matter in order to grow, so keeping these factors under control in your garden can help keep mushrooms at bay.
Ensure your garden soil drains properly after rain or irrigation. Soil that stays soggy for extended periods is the perfect environment for mushrooms to form.
Mulch can also contribute to moisture problems. Organic mulches frequently house fungal spores that can later turn into mushrooms. If your garden has recently succumbed to a mushroom problem, it may be time to replace your mulch.
Organic material is great for plants. However, excess matter can promote fungal activity. Remove things like logs, lawn debris, and animal waste that will rot and encourage mushrooms in your garden.