Contamination

Healthy mycelium is bright white, fluffy or wispy, no smell or a faint mushroomy / nutty smell. It looks alive.

Contamination shows colour (green, black, pink, grey), or a slimy sheen, or a sour / sweet / cheesy smell. Trust your nose — it's faster than your eyes.

Starts as a faint white patch that's already too aggressive for the mycelium. Within days it turns forest-green and outpaces everything.

If you catch a small patch before it sporulates (turns green), you can sometimes cover it with salt or hydrated lime. Once green, the bag is finished — outdoors it goes, never indoors near other grows.

Looks like spider web — fine, grey, fluffy, expanding hourly. Most often appears on the casing layer of fruiting grows.

Hydrogen peroxide 3% sprayed directly on cobweb can stop it if caught instantly. If it's been there a day, the block is done.

Bruising is mechanical — handling, pressing, cold shock — and shows up as crisp blue, brown, or yellow spots that don't spread.

Bacterial blotch is wet, slimy, smells sour, and spreads across pin clusters. It loves stagnant high humidity. Fix it with airflow first, then surface sanitation.

Toss if: green mould, black mould, slimy yellow goo, sweet / sour / vomit smell, or contamination is spreading faster than mycelium.

Save if: a small patch caught early, mycelium is racing ahead, the smell is still right. Cut it out with a sterile knife, treat with salt/lime, and watch.

When in doubt, toss outdoors. One contaminated bag in your grow room contaminates everything.