You’ve followed the steps, your mycelium is growing, and anticipation is high for your first mushroom harvest. But what happens when things look… a little off? Don’t worry! Every mushroom cultivator, from beginner to expert, encounters challenges. It’s a natural part of the learning process.
This guide is here to be your troubleshooting companion. We’ll cover the most common problems new growers face, explain what’s likely causing them, and provide simple, actionable solutions to get your project back on track.
Problem 1: Nothing is Happening! My Mycelium Isn’t Growing.
You’ve inoculated your substrate, and a week later, you see no signs of the beautiful, white mycelial growth you were expecting.
Likely Cause: The most common culprit is temperature. If the colonization environment is too cold, the mycelium will grow incredibly slowly or go dormant. Less commonly, the spawn itself may have been old or damaged.
The Fix: Find a warmer spot for your bucket or bag, ideally between 65-75°F (18-24°C). A closet in a heated room or the top of a refrigerator often works well. Be patient; sometimes it just needs a little more time.
Problem 2: I See Green, Blue, or Black Mold.
You check on your colonizing substrate and see fuzzy patches of green, black, or even bright orange mold.
Likely Cause: Contamination. This means a competing mold or bacteria has established itself in your substrate before your mushroom mycelium could take full control. This almost always happens due to incomplete pasteurization or un-sanitized equipment during inoculation.
The Fix: Unfortunately, once a significant contamination takes hold, it’s very difficult to save the project. The best solution is to discard the contaminated substrate (add it to your outdoor compost pile, where it can still do some good) and start over, paying extra close attention to cleanliness and proper pasteurization. Think of it as a valuable lesson learned.
Problem 3: My Mushrooms Are Long and Skinny with Tiny Caps.
Your mushrooms are growing, but they look strange and leggy, not like the robust pictures you’ve seen.
Likely Cause: This is a classic sign of high carbon dioxide (CO2) levels and not enough Fresh Air Exchange (FAE). The mushrooms are literally stretching out, searching for more oxygen.
The Fix: Increase the airflow. If your bucket is in a tote or “fruiting chamber,” open it and fan the air with the lid two to three times a day. If it’s in a small, stuffy room, try opening a door or using a small fan on a low setting on the other side of the room to gently circulate the air.
Problem 4: My Mushroom Pins Formed, but Then They Dried Up and Died.
You were excited to see tiny pins forming, but they stopped growing, turned dark, and shriveled up. This is called “aborting.”
Likely Cause: The most common reason for aborts is a lack of humidity. The pins are extremely vulnerable to dry air in their first few days of life.
The Fix: Increase your misting frequency. Aim to mist the sides of your bucket or fruiting chamber 2-4 times a day, ensuring that the air is always moist and you can see fine droplets on the surfaces. Be careful not to spray the pins directly, as this can sometimes damage them.
Problem 5: My Mushroom Caps Are Cracked.
The caps of your developing mushrooms look dry and cracked, almost like a desert floor.
Likely Cause: Again, this points to low humidity. The air is too dry, causing the surface of the mushroom cap to lose moisture and crack as it expands.
The Fix: This has the same solution as aborting pins. Increase humidity by misting more often. You want the environment to feel like a damp forest floor.
Learning to grow mushrooms is a journey of observation. Don’t be discouraged by a setback. Every challenge is an opportunity to learn more about the needs of these incredible organisms and to fine-tune your process. By paying attention to temperature, cleanliness, fresh air, and humidity, you’ll be on your way to a successful and delicious harvest.