1. Freshly cut hard wood logs like Oak, Beech and Birch are best. They should be less than 6 weeks old and have a diameter of 10 to 20cm and 50cm long. Older logs will have dried out and have other weed fungi growing on them. The bark should be clean and intact, cut any branches off.
2. Using a 9 or 10mm drill bit, drill holes every 15cm along the length of the log with the first and last holes 3-4cm from the ends. Start the second row 10cm in further round the log. For a 10cm diameter log which is 50cm long use 10 dowels, (3 dowels to the first row, 2 to the next, then 3, and 2 in the last row.)
3. Tap each dowel into the drilled holes flush with the surface of the bark.
4. Wrap the logs in plastic or put in a bin liner to retain moisture and keep clean. Place in a cool garage or shed or in the garden covered with leaf litter. The log will be covered with white mushroom mycelium after about 6-12 months depending on the size of log, mushroom species and type of wood.
5. When colonised remove from the bag and place log outside in the garden, protect from direct sunlight and drying winds. If logs begin to dry out soak in water for 24 hours rather than wet with a hose. Mushrooms will fruit according to climatic conditions - normally after cold rain following a warm spell. Shiitake mushrooms can be "shocked" to stimulate fruiting - immersion in cold water for 48 hours during warm weather.
CAUTION: Care should always be taken in sighting the fruiting mushroom. Some people are allergic to mushroom spores. In general avoid confined or poorly ventilated spaces for fruiting areas and pick mushroom before cap is fully unrolled.