Getting started with agar — what beginners need to know

Agar work is using petri dishes filled with nutrient agar as a medium for growing and selecting mycelium. Key uses: cloning fruiting bodies (preserving superior phenotypes), isolating single-spore genetics, purifying contaminated cultures, building a living culture library. The main skill barrier is aseptic technique — every agar manipulation is done under a laminar flow hood or in a still air box.

Minimum equipment: still air box (a glove box works), pressure cooker for sterilization, petri dishes (polystyrene, stackable), agar (LME agar or PDA are standard), glass mason jars, alcohol lamp or torch, scalpel handle + #22 blades. Total cost: $50-100 if you don't have a flow hood. A flow hood ($200-400) dramatically reduces contamination rate but isn't required to start.

Common beginner mistake: rushing transfers before the agar has fully solidified and cooled, or not allowing the agar to dry for 24 hours before use. Wet agar surface leads to bacterial contamination from condensation. Secondly: opening petri dishes in non-aseptic conditions, even briefly, introduces contamination. Treat every second the dish is open as a contamination risk.