Molds on Magic Mushrooms: How to Know IF Your Shrooms are Contaminated?

Magic mushrooms are an exciting piece of fungi. Primarily because of their psychedelic properties. It’s these psychedelic properties that make it an exceptionally sought-after mushroom. Since they can be found in the wild, many people go through foraging for them.

Foraging can be a relatively fun activity in itself. However, it’s also an activity that not everyone has the privilege to do. For example, some people may not have any kind of magic mushrooms accessible to them. In addition, some people don’t find foraging all too enjoyable. Fortunately, there is an alternative.

Another way to get your magic mushrooms is to grow them yourself. Today, several techniques (also known as TEKs) help you grow your shrooms from home. What’s more, the process is relatively straightforward. However, there are still some disadvantages that can come with this method. One perfect example would have a contaminated batch.

Despite how specific these TEKs can be, they are still prone to contamination. This is especially if not done correctly. Having mold on mushrooms magic can not only be a real pain but can also be very dangerous. That is why knowing how to identify any form of contamination is essential.

With that in mind, this must serve as a mushroom contamination guide for those who choose to grow shrooms.

What is Contamination?

molds on magic mushrooms
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When you talk about contamination, you talk about any unwanted growths. These organisms are found on your mycelium or shroom substrate.

Contamination can come from several sources, such as in the air, water, or soil. They can also be found in the substrate you use, their growing environment, and even in your inoculant. Even pests can be a kind of contaminant that you can find in any mushroom culture.

Contamination of any kind can ruin an entire mushroom culture. This is mainly because they can spread relatively quickly. That’s why you must identify any forms of contamination as soon as possible. By placing them early can help save parts of your culture. This will help spare the shrooms from any contaminants. That, in turn, will ensure that it does not go to waste.

Fortunately, the identification of contaminants can be a relatively easy task. This is because magic mushroom cultures are white. Should there be any normal deviation in color, these should usually come in blue or yellow. Any other color would indicate that your batch has been contaminated.

Different Kinds of Contaminations

There are three main types of contaminants: mold, bacteria, and pests. Mold on magic mushrooms might seem like a funny idea since they’re both technically fungi. But, you can still get moldy magic mushrooms if you aren’t careful about contamination.

Then, there are bacteria. These microorganisms can reduce rather quickly if left unchecked. Fortunately, sterilizing and pasteurizing your substrate can mitigate this.

Lastly, you have your pests. These insects can gnaw away at your culture. It can also carry diseases that can infect and destroy your culture. If not appropriately sanitized, the shrooms will be in danger of pests. That is why you should clean and keep the shrooms in an airtight area.

The Signs of Contamination

white molds on magic mushrooms
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Having a contaminated culture can be very disheartening. This is mainly because you can potentially lose your entire batch of mushrooms. Learning how to spot contamination in its early stage will help. This will prevent it from spreading and getting any worse. 

The first and most apparent sign of contamination would be discoloration. Molds are one contaminant that would usually manifest in very distinct bright colors. If you find blue, green, black, or gray patches in your setup, you most likely have a contaminated culture.

However, it’s also worth noting that if you happen to find blue stains on your mycelium, this may not be mold. This is just bruising. This occurs when your substrates press against each other in the container. 

Another sign of fungi-related contamination would be what is known as sectoring. Usually, a typical mushroom culture will uniformly grow through the substrate. The roots and hyphae (branches) may go in different directions. But they will eventually converge. If you see areas with no merging, this is a sign of a foreign fungal contaminant.

These types of fungi have color and appearance that allows them to blend into the culture quickly. However, some fungal contaminants aren’t so easy to identify. Using a microscope is the only way to identify these contaminants. This will reveal their hair-like appearance with a bubble-shaped tip.

Bacteria is another contaminant that can try to grow in your culture. You’ll usually find patches of slime on your substrate when bacteria have colonized it. It can also be found on the mycelium itself. Bacteria contamination can also manifest as yellow and brown stains. There are instances it will have gel-like or crusty textures.

Yet another sign of contamination would be the appearance of a powder-like substance. Another tell-tale sign is dust on the mycelium. This is another sign that another organism is invading your substrate. To find these, you’ll need to use a magnifying glass.

Most Common Molds Found in a Magic Mushroom Culture Kit

Several kinds of contaminants can plague your mushroom culture kit. One of the most common kinds of contaminants would be molds. Unfortunately, these magic mushrooms mold can come in a variety of types. Usually, you can identify them by color. Some of the most common kinds would be the following:


blue-green molds

The Penicillium species usually cause blue-green molds. This is the same species of mold that grows on your bread and cheese. Ironically, this is also the very same species responsible for Penicillin.

You won’t usually find signs of Penicillium in your culture in its early stages. This usually starts with a white mycelium. Then, however, they grow relatively quickly, growing into a blue-green powder-like mold. This growth can also be bordered by white growths, which are signs of new mold growth. Aside from that, this kind of mold gives off a musty odor.

This blue-green mold can grow on any substrate, such as grains, wood, and rice flour. They have a predilection for growing off of carbohydrates.

Black Mold

Black molds can be attributed to the Aspergillus species. While they are typically black, other species can also take on green, blue, brown, or yellow. Sometimes, they can even have a combination of colors.

Aspergillus mycelium is usually light grey. This is like the color of the mycelium of mushrooms. Black mold colonies typically form a ring with a dense mass of mycelium around it. These molds give off an oily and musty odor. Before smelling any mold, there is one warning. Remember that some species of this type of mold are poisonous.

These types of mold have a preference for pH levels that range from neutral to basic. Some also love high temperatures.

Green Mold

close up view of green molds

The cause of green mold would be the Trichoderma species. This is an aggressive-growing type of mold. This mold proliferates in round colonies, starting as light gray. Eventually, it gives off its characteristic green spores. Unfortunately, it’s hard to identify the culture’s degree of contamination. This is due to how late this species gives off its spores.

This mold is a parasite to both the mushroom and its mycelium. Usually, the mold will cause mushrooms to have brown blotches or ulcers on their stems or caps. Cultures contaminated by this mold will also be covered in mildew.

Warm and humid environments with low airflow are the ideal conditions for this type of mold to grow.

Other Molds Usually Found in Cultures

Aside from the types mentioned earlier, other types of molds can prey on shroom cultures. Some of these different molds are as follows:

Cobweb Molds

up close view of cobweb molds
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The Hypomyces rosellus is also known as cobweb molds. This is due to their appearance. Cobweb molds are another rapid-growing mold. It starts as small patches scattered around the culture. This then spreads quickly over the substrate surface.

It starts gray and then eventually takes on a whitish color. This mold can also be found in wild mushrooms. This means it can spread relatively quickly during spore collection.

This type of mold loves humid environments and can take over an entire culture in less than two days. Overrun cultures usually have a fluffy mass covering them, which will then lead them to rot.

Brown Molds

The Botrytis cinerea is another rapidly-growing mold that plagues cultures. This is also known to grow on fruits, such as grapes. These molds are initially white in appearance, then turn gray. As its spores mature, they become golden brown to cinnamon.

This mold typically grows above the substrate of the culture. It spreads on the casing of the culture, especially if the layer is rich in wood tissues. Humid environments with moderate temperatures are the ideal conditions for brown mold growth.

Lipstick Mold

This kind of mold may have an appearance like frost. It starts from this frost-like stage and then forms white balls. This is usually found in colonizing a culture’s casing layer. But can also grow on other substrates.

The mold eventually becomes pink as it develops. As its spores mature, it becomes red. It then takes on a dull orange color when it gets older.

Fortunately, this mold is usually uncommon.

Pink Mold

pink molds close view

Pink molds are caused by Trichothecium roseum, which parasitizes fungi. This rapidly-growing fungus starts off white. Eventually, it takes on a pink or peach color with spore production. Similar to Penicillium in appearance, it has an appearance similar to powder.

Pink Mold/Red Bread Mold

Common in agar and grain substrates, this red bread mold can be found anywhere in nature. Along with this, it can grow rapidly. Because of this, it becomes difficult to eliminate. Therefore, any culture contaminated by this mold must be immediately destroyed, followed by a thorough cleaning of the environment where you grow your shrooms.

Black Bread Mold

Black bread mold is a very commonly occurring mold. This rapidly-growing mold has a dense mycelium, initially white. This grows as a layer above the substrate. Eventually, the mycelium takes on a grey appearance. The mycelium then becomes black due to spore production.

dry bubble infection on a magic mushroom
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Dry Bubble

This white mycelium is initially found on a culture’s casing layer. It eventually becomes yellowish-gray as it develops. It becomes greyish-brown and has a leather-like texture. Deformed mushroom pins are characteristic of the dry bubble.

Mushrooms infected in their later stages become crooked. Others have tilted caps and stems that bulge at the base.

Bacterial Contaminants

Bacteria can also prey on mushroom cultures, given the ideal conditions. Some signs of bacterial growth in the culture are the following:

Wet Spot/Sour Rot

Bacillus bacteria are known to cause “sour rot” or “wet spots.” This contamination comes in the form of a brown to dull gray colored slime, which smells like dirty socks. It is called a “wet spot” because the bacteria multiply quickly and appear wet on the substrate as a result.

Bacterial Blotch

bacterial blotch on a magic mushroom
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Bacterial blotches can appear due to excessive moisture in the culture. These blotches appear as yellow spots on the caps. Excessive humidity can happen due to a humid environment. Another reason for excessive moisture is having mushrooms wet for an extended period. Eventually, the mushrooms can become brown and have a slimy layer on them due to the bacteria. This contamination also gives off a rather foul odor.

Dealing With Contamination

There are several ways that you can deal with contamination. First, you can prevent it altogether. But that would entail taking the necessary precautions. First and foremost, you’ll need to keep a clean environment. This means sterilizing all the instruments you’ll be using. Sanitize all the materials and surroundings in your culture’s area as well.

The best way to not taint the shrooms is to follow whatever instructions you have. Another way to help deal with contamination would be to strictly adhere to the method you’ll use. These are tried and tested methods, so there is always a correct way to go about them.


For anyone growing their mushrooms, contamination is an unwanted outcome. Having a contaminated culture means that it has gone to waste. This is mainly if not dealt with properly.

Fortunately, you can help prevent contamination from ruining your culture. This is done by identifying the different kinds of contamination. You can help mitigate any further contamination and even save your culture. This is done by identifying them as early as possible. You could prevent your other cultures from contamination if some were unable to be saved.

While growing your shrooms may be tedious and complicated at times, it’s still a fun activity to engage in. Even if you don’t get it right the first time, you can learn from it and do even better next time!

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