Mushroom Contamination: How to Identify, Prevent, and Respond
About This Video
Contamination is the primary failure mode for new mushroom cultivators, and this video from Shroomscout is the most thorough visual reference available for identifying what you're dealing with. Green (Trichoderma), black (Aspergillus), pink/red (Neurospora), and bacterial wet rot are all shown at multiple stages — because catching contamination early is the difference between losing one jar and losing an entire grow.
The prevention section is as valuable as the identification content. The video goes beyond 'work clean' to explain the specific vectors where contamination enters: inoculation technique (the single highest-risk moment), substrate moisture levels that favor bacterial growth, and the failure mode of opening tubs too early. The 'still-air box vs. flow hood' section gives honest guidance on when a still-air box is sufficient (most home grows) and when the investment in a flow hood pays off.
Key Takeaways
- Green mold (Trichoderma) is the most common contaminant — discard affected jars immediately in a sealed bag away from your grow space.
- Pink or red growth is Neurospora (bread mold) — it spreads aggressively via airborne spores and can contaminate an entire grow room quickly.
- Wet rot (bacterial contamination) is caused by overly moist substrate — a handful should yield only a few drops when squeezed.
- Inoculation is the highest-risk moment — needle sterilization between jars, quick technique, and still air are the three non-negotiables.
- A still-air box (SAB) is sufficient for most home cultivation; a flow hood is worth the cost only if you are working with agar or doing regular large-scale inoculations.
Dive Deeper
Continue exploring this topic on LearnShrooms: