Questions?
order
Questions?
Questions?
Questions?
Think you might have contamination in your mushroom grow bag? Take a deep breath, relax, and read below to find out!
Contamination is any unwanted organism that takes over your mushroom growing environment and threatens the health of your mycelium. Your mushroom grow bags are a delicate environment, and sometimes other fungi or bacteria sneak in and threaten your grow. Contamination happens to even the most seasoned mushroom cultivators, so don’t kick yourself. Learn from it, and always be looking for ways to improve your sterility, cleanliness, and growing methods.
This guide should give you a clear understanding of the common contaminants that you may come across in a mushroom grow bag. Take a look at the contamination examples below. If, after reviewing this document, you still suspect contamination, isolate your bag from any other bags and email us a photo before you throw your bag away. Our expert mycologist support team will confirm the contamination and help keep your mushroom dreams alive and thriving! (whether that means replacing your bag or troubleshooting your grow)hav
Folks can sometimes confuse healthy mycelium with contamination. In the early stages, healthy mycelium usually appears as soft, wispy white strands that gradually thicken into dense, structured growth. But mycelium might look a little fluffy at first or even have odd coloring as it grows. It’s easy to think something might be amiss, but give it a minute—it could just be the natural growth of your healthy mycelium developing. Rushing to conclusions too early can lead to unnecessary worry and may result in throwing away a bag that has potential.
Here’s some examples of healthy mycelium:
Now, onto the real “bad guys”…
By far the most common contamination found in your mushroom grow bag, Trichoderma starts off looking suspiciously like healthy white mycelium. But, given a little time, it reveals its true colors, literally, by turning a bold shade of emerald green (sometimes gray). By the time you see green, it’s already throwing a spore party you definitely didn’t RSVP for. It can be aggressive and often moves quickly through your grow bag!
Trich is everywhere. The spores are literally in every breath we take. It lives in soil, it floats in the air. It thrives in damp, warm environments… So basically, the exact same conditions your dung-loving mushrooms love. Coincidence? We think not.
Bad news: If you see green, your bag is toast. Once Trich gets comfy, it spreads fast, releasing spores into the air that can infect nearby grows. So, here’s the plan:
Bacillus is like the ninja of contaminants; sneaky, quiet, and it can show up when you least expect it. Unlike the loud and proud Trichoderma, Bacillus doesn’t have green fuzz or visible mold to warn you. It usually manifests as a slimy or watery substance, often found around the edges of your substrate. After Trich, this is probably the second most common contaminant found in all-in-one mushroom grow bags.
Bacillus thrives in a wet environment. If you’ve over-misted at the fruiting stage or have a bit too much moisture inside your grow bag during prior stages, Bacillus is happy to take advantage. It starts by breaking down the substrate, creating a nasty, wet, and sometimes foul-smelling mess.
Bacillus usually shows up as a slimy or watery spot, often with a smell similar to sour milk. It can be tough to spot, so keep an eye out for moist, decaying areas where the substrate might be breaking down. It can also show up as a slight “wetness” to the surface of the bag. Sometimes a “popped” rye grain can be confused for Bacillus. It may appear moist around the burst grain. Look carefully though, as a popped rye grain is not Bacillus and nothing to be concerned of. As always, shoot us an email to confirm.
Bacillus is a genus of bacteria commonly found in soil, water, and decaying organic matter, playing a vital role in nutrient cycling and soil health. In our all-in-one mushroom grow bags, Bacillus can naturally occur during the cultivation process. While some Bacillus strains can be beneficial, aiding in decomposition and nutrient availability, others may contribute to contamination if they proliferate unchecked.
Bacillus is a slow mover and will stunt growth. Take the following steps if you suspect Bacillus:
Orange Bread Mold coins its name from its distinct orange color and its tendency to infect bread products. As most substrates in all-in-one mushroom grow bags are made of grain, it unfortunately enjoys mushroom grow bags as much as bread. Like an angry, orange orangutan swinging through the jungle trees, it shows up uninvited, spreads quickly, and can wreak havoc on your precious mushrooms. Note: we love orangutans and they’re usually very peaceful—just needed a good analogy. 😉
Orange Bread Mold’s distinctive orange hue makes it easy to spot. It often appears in patches, sometimes mixed with white mycelium and can spread quickly if not dealt with. It can sometimes sneak in with other molds. Just don’t confuse it for metabolites, (covered below).
Orange Bread Mold thrives in humid, stagnant conditions, making it a common invader in improperly ventilated setups. It can hitch a ride on unsanitized tools, hands, or even airborne spores from nearby contamination. If your mushroom grow bags are struggling with excess moisture, this mold sees it as an open invitation. It’s usually a sign that your environment is a little too warm or moist.
Bacillus is a slow mover and will stunt growth. Take the following steps if you suspect Bacillus:
Pucker up. Red Lipstick Mold is one of the more dramatic molds you’ll come across in mushroom cultivation. This is one of the molds you’ll likely see in an all-in-one grow bag, so keep an eye out for this dangerous vixen.
This mold doesn’t shy away from attention. Red Lipstick Mold appears as bright red or pinkish patches, kind of like the lipstick stain your Grandma leaves on your cheek every Christmas. It often presents a sticky or gooey texture, making it quite distinct from the dry, powdery molds you may be more familiar with. This mold thrives in overly damp areas, taking advantage of any moisture imbalance in your grow space.
Aspergillus niger appears as black or dark brown patches, often looking like a fine dusting of soot or pepper. While it’s commonly found in the environment, in mushroom cultivation, it’s a major red flag. Not only can it ruin your grow, but inhaling its spores isn’t something you want to mess around with.
At first, you might mistake this mold for something harmless. It often starts as faint white or grayish fuzz before darkening into black or dark brown spots. These spots can appear dry and powdery or slightly raised. Over time, Aspergillus niger forms a dense, black mass that can release spores into the air… bad news for both your mushrooms and your lungs. But don’t mistake this contamination for dark, purple bruising that might occur on mushrooms during the fruiting stage or for mature mushrooms “dropping spores” after their veils have broken from the stems—these spores can look like black dust and are harmless. Keep your eye out for any of these signs of Aspergillus niger:
Bacillus is a slow mover and will stunt growth. Take the following steps if you suspect Bacillus:
Cobweb Mold is the master of disguise in the world of mushroom cultivation. At first glance, it can look like mycelium, tricking growers into thinking all is well. When using a mushroom grow bag, it can be particularly tricky to see through the opaque bag. This mold spreads aggressively, forming fine, wispy strands that can engulf your substrate in no time. If left unchecked, it can suffocate your grow within a matter of days.
Unlike the strong, structured growth of healthy mycelium, Cobweb Mold has a distinct look:
If you spot yellow or amber-colored liquid pooling around your mycelium it’s usually NOT contamination, but actually Metabolites, sometimes called “mycelium pee”. Metabolites are natural excretions produced by mycelium as a defense against bacteria or stress. Seeing a little of this liquid is completely normal, especially as your grow progresses. However, excessive metabolite production could indicate your mycelium is fighting off contamination or dealing with less than ideal conditions.
If your bag is looking more like a juice box than a mushroom grow bag, examine your bag carefully for contamination and make sure your growing conditions are as good as you can make them. Proper airflow, balanced humidity, correct temperature (between 70°F to 77°F) and clean conditions make all the difference.
Beginner growers often second-guess what they’re seeing in their bags, and that’s totally normal. That’s why we made this guide! This guide should give you a good idea as to whether you’re seeing healthy mycelium or dealing with naughty contamination. If after reviewing the guide, you’re still unsure whether something is healthy mycelium or contamination, ask for a second opinion from our support team ([email protected]). Mushroom cultivation is a learning process, every experience helps you grow (literally and figuratively)!
Mush Love,
The Magic Bag Team
