Diagnose
Symptom-first. You do not know you have Trichoderma — you know something is green. Find what you are looking at, whether it can be saved, and what caused it.
12 pages
Green or blue-green patches on substrate or grain
Green mold in a mushroom grow is almost always Trichoderma. How to tell it from healthy mycelium, whether the tub can be saved, and what caused it.
Fuzzy grey growth, wispy like cobweb
Cobweb mold is grey, wispy and alarmingly fast — and unlike most contaminants it's usually treatable. How to identify it, treat it, and fix the humidity problem underneath.
Grain jars not colonising, grey slime, sour smell
Grey-brown gluey patches, a sour smell, and mycelium that stops at the edge of them. Wet spot is bacterial, it's not treatable, and it almost always means the pressure cooker.
Long thin stems, tiny caps, stretching mushrooms
Leggy, pale, stretched mushrooms with undersized caps are a fresh air problem, not a light problem. What CO₂ does to fruiting bodies and how to fix it without drying the tub out.
Pins forming then aborting, primordia dying back
Pins that go clear, yellow or grey and stop growing are almost always an environmental shock rather than a disease. The five causes, in the order worth checking them.
Yellow or amber liquid on the mycelium
Amber droplets on healthy mycelium are normal metabolic exudate. Yellow liquid that's spreading, smells, or sits in a puddle is not. How to tell them apart.
Wet slimy patches on fruits, sour smell
Sunken brown lesions on caps, a slimy film, and a smell that's clearly wrong. Bacterial blotch is a surface-water problem, and the fix is drier air rather than a treatment.
Black fuzzy growth with pinhead tips
Tall grey fuzz topped with black pinheads, growing fast on wet substrate. Rhizopus is not salvageable and is a genuine respiratory concern — how to identify and remove it safely.
Bright orange or peach-coloured powdery growth
Bright orange powdery growth that spreads through filter patches and plastic. Neurospora is rare, unmistakable, and the only contaminant that justifies clearing a room.
Mycelium stalled, no visible growth
Growth that stopped without any visible contaminant. Seven causes worth checking in order, and how long to wait before concluding it's actually dead.
Fruits growing sideways or inside the bag
Mushrooms growing horizontally, curling back on themselves, or fruiting into a sealed bag. Gravity, air and light all steer a fruiting body — here's which one is steering yours.
Contamination appearing after the first harvest
A block that fruited cleanly and then went green between flushes. Why post-harvest contamination happens, whether the remaining flushes are worth chasing, and how to harvest so it doesn't.
By stage
In grain
In bulk substrate
During fruiting
- Green or blue-green patches on substrate or grain
- Fuzzy grey growth, wispy like cobweb
- Long thin stems, tiny caps, stretching mushrooms
- Pins forming then aborting, primordia dying back
- Yellow or amber liquid on the mycelium
- Wet slimy patches on fruits, sour smell
- Fruits growing sideways or inside the bag
- Contamination appearing after the first harvest