Cultivated Mushrooms

How They Grow

Wood Decomposers

The techniques for growing mushrooms on wood began in the far east 2000 to 3000 years ago. Wood infected with the desired mushroom were mixed into log piles in the hope that the fungus would spread to the logs in the pile. China is usually cited as the place where log cultivation began, but it has spread to many countries in South-East Asia. Log cultivation is still widely employed today. The modern method involves drilling or cutting holes in the logs, which are filled with mushroom spawn. Log cultivation is a long term project taking 18 months to 2 years from inoculating the logs to producing the first mushrooms. The logs will produce mushrooms for 5 or 6 years.

A faster technique, using wood shavings and sawdust, was developed in Japan after the Second World War. The shavings, mixed with water and bran, are put into bottles or bags to form an artificial log. This is sterilised and then inoculated with mushroom spawn. The artificial logs are incubated in a controlled environment until they are ready to produce mushrooms. This process takes from 1 to 6 months to produce a crop, depending upon the mushroom being cultivated.

A wide range of mushrooms are grown with this method: oyster mushrooms, shiitake, hen-in-the-wood, enokitake, wood ears, nameko and white cloud to name a few.

Plant Decomposers

Growing mushrooms on composted straw is the most common method used in Europe, usually to grow the white Agaricus mushroom. The earliest records of this method are from 16th centuary France where mushrooms were grown in the catacombs under Paris. From this the cultivaed Agaricus mushroom has become known as the champignon de Paris or Paris mushroom.

Straw is mixed with animal manure and water and composted. After composting the mushroom spawn is added and the compost is made into beds about 30cm deep. and maintained under controlled conditions until the compost is fully colonised by the mushroom. At this stage the bed is covered with a caseing layer, usually peat based, to a depth of about 4cm. This process initiates mushroom formation and the first crop is ready for harvest about a week later.

This method was developed to grow Agaricus mushrooms: field mushroom, horse mushroom and Agaricus bisporus, but a wide range of other mushrooms would be suited to this method: fairy ring, blewits, parasols, puffballs and funnel caps.

Mycorhizal fungi

These are mushrooms that only grow in association with specific plants, usually trees. They include many popular edible mushrooms: penny bun, chanterelle, horn of plenty, charcoal burner, saffron milkcap, truffles and brown birch bolete.

For these mushrooms it is neccessary to grow the tree aswell as the mushroom. The young tree sapling is innoculated with the mushroom mycelium and then planted out in an appropriate site. With a bit of luck when the tree mature you get some mushrooms. It is a long term project, taking many years to get the first crop, but once established will continue for many more years.