MycoForge | Mushroom Growing Supplies UK – Beginner & Advanced Guides

How to Inoculate a Grain Spawn Bag (Liquid Culture or Spore Syringe)

Objective: Introduce mycelium into a sterilised grain bag safely to start mushroom cultivation.

Materials Needed

Sterilised grain spawn bag (with filter patch)
Liquid culture (LC) or spore syringe
Alcohol wipes or 70% isopropyl alcohol
Gloves
Face mask (optional but recommended)
Lighter or alcohol lamp (for flame sterilisation, if needed)
Syringe needle (if not pre-attached)

Step 1: Prepare Your Workspace

Work in a clean area to reduce contamination (e.g., still air box or near a HEPA-filtered space).
Wash hands thoroughly and wear gloves.
Wipe down the workspace with 70% isopropyl alcohol.

Tip: Minimise airflow and avoid drafts, which can carry contaminants.

Step 2: Prepare the Bag

Shake the grain bag gently to distribute grains evenly.
Inspect the bag for any cracks or leaks. Do not use if compromised.
Remove the outer layer of the filter patch to expose the injection site (if applicable).

Step 3: Prepare the Syringe

For Spore Syringe: Shake well to suspend spores evenly.
For Liquid Culture: Shake gently to mix the mycelium without creating bubbles.
Wipe the needle with alcohol.

Step 4: Inoculation

Insert the syringe needle through the bag’s injection port or filter patch.
Inject 3 mL of Culture 5ml for Spawn (adjust depending on bag size).
Move the needle around slightly inside the bag to distribute spores or culture.
Remove the needle carefully and wipe any drips with an alcohol wipe.

Step 5: Seal and Incubate

Reseal the injection port (if necessary, with tape or self-sealing patch).
Shake the bag lightly to mix inoculum with grains.
Place the bag in a dark, warm location appropriate for the mushroom species (typically 18–26°C).

Step 6: Observation and Maintenance

Check daily for signs of colonisation (white mycelium growth).
Remove any contaminated bags immediately.
Fully colonised bags are ready for fruiting or expansion.

Contamination Risk Notes

Inoculation TypeContamination RiskNotesSpore SyringeHigherSpores contain more airborne contaminants; slower colonisation gives more time for mold to develop.Liquid CultureLowerMycelium is already established, outcompeting contaminants; faster colonisation reduces contamination window.

Summary: Use liquid culture for higher success rates if you want faster colonisation and lower contamination risk. Spore syringes are easier to store long-term and start new strains but carry slightly higher contamination risk.