Interactive lesson

Mushroom problems and safety, step by step

Interactive lesson: hygiene, moulds on bags, problems on logs, mushrooms that grow oddly, pests, spores and wild mushrooms.

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The whole lesson as text

1. Hygiene

Moulds are everywhere, but you can give the mycelium the head start.

From clean to dirty — On any given day, work with spawn and new bags first, and only then pick, clean and carry out old bags. Never the other way round.
The room before the season — Take everything out, sweep damp, wash the shelves with hot water and detergent. Limewash the walls with hydrated lime, wearing goggles, gloves and a mask.
Hands and tools — 70 % alcohol on hands, knife, table and spoons before filling. Clean clothes, not the ones from the barn; fine mesh on the windows against gnats.
Substrate and log — Fresh, dry straw and pasteurising at 65–75 °C with a thermometer, not “roughly”. Every bag, log and jar has a number in the log.

Why: Almost every problem has five causes: dirty substrate or work, too much heat, too much or too little water, too little air and poor spawn. Hygiene prevents most of them.

Never grow mushrooms in a room with apples, potatoes or preserves, or next to compost and manure.
If there was a lot of contamination, leave the room empty and dry for 1–2 weeks.

2. Moulds on the bag

A coloured patch in the middle of white mycelium means someone has arrived.

Green patch — White at first, then dark green dust: trichoderma, the most common enemy. The cause is dirty work, weak pasteurising, old spawn or too much warmth.
Orange dust — Orange or pink dust that grows within a couple of days: neurospora. Close the bag in a second bag at once, it spreads fast.
Sour smell, water — Wet, brown or yellow, water at the bottom: bacteria. Throw it out; next time drier straw and more holes.
Don’t open it in the house — Put a contaminated bag into a second, closed bag and carry it out. Hot compost well away from the mushrooms, 30 cm deep in the ground or the bin; wear an FFP2 (N95) mask.

Why: The colour and smell tell you who has arrived. One green bag releases millions of spores that contaminate every new run within two weeks.

For beginners it is simpler: a green bag goes out, straight away.
Slimy grain in a jar: sterilise the jar closed, then throw out the contents.