What's wrong with my grow?

A competing mould. It spreads fast and releases spores that contaminate other grows nearby.

Verdict: bin it. Don't try to save a green kit.

Grey-white, wispy growth that climbs over mushrooms. It thrives in still, very humid air — and is easy to stop if you catch it early.

Verdict: treatable. Watch it for 48 hours.

Yellow droplets are the mycelium's own waste liquid, often after stress or heat. Not a contamination by itself.

Verdict: keep going. Recheck if it smells sour.

Mushrooms stretch their stems looking for air. They're safe to eat — just less pretty and less weight per flush.

Verdict: harvest and adjust — the next flush will be better.

No pins usually means the surface dried out or the room is outside the species' range. Most kits recover.

Verdict: give it 10 more days.

Slimy, grey or yellow grain that smells sour or sweet. Bacteria usually come from grain that was too wet or not sterilised long enough.

Verdict: bin it. Bacteria don't clear up.