Rosemary Ann Ogilvie shares the joys of growing (and eating!) your own mushrooms.
First, it must be admitted that mushrooms rank high on the scale of unreliable crops for home growers, thanks to their unpredictable nature and the lack of sophisticated climate control and pasteurisation equipment used by commercial growers. However, patience, perseverance, trial and error – and scrupulously clean hands at every point – can produce abundant crops in tiny spaces. And the challenges make it all the more rewarding when that first crop appears!
Choosing oyster mushrooms increases your chances of success as these are the easiest and most forgiving to grow – quite surprising, given their hefty retail price tag. Old paperback books, phone directories, stacked egg cartons, and cardboard cartons cut into squares about the size of a paperback make ideal substrates. You’ll also need a large, strong polythene bag such as a kitchen tidy bag, oyster mushroom spawn (available from Aussi Mushroom Supplies www.aussimushroomsupplies.com, or Forest Fungi www.forestfungi.com.au) and a lidded cardboard box or other container large enough to hold the substrate.
* First, pasteurise the substrate material. Boil enough water to cover it. While water is boiling, with freshly washed hands take a generous few handfuls of the spawn – again, depending on the size of the substrate – and break it into small grains. Place the substrate material in a large clean baking dish. Pour in the water, and press down on the material to keep it under the water until bubbles stop rising. Leave until cool, then drain off excess water.
* Generously sprinkle the spawn in between egg cartons or cardboard sheets, or over several pages at the beginning and end and through the book. The more spawn you use, the quicker the mushrooms will grow and the less likelihood of contamination.
* Press down hard on the material to make it as flat and tight as possible. Place into the polythene bag, close the top of the bag and bind tightly with string or tape. Sealing it this way retains the moisture, and also increases carbon dioxide levels, which prompts the mycelium to grow.
* Place the bag into the container and close the lid. Store in a warm spot: for optimal production: the temperature should range from 10-21°C for the King, Grey, Tan and White Oyster mushrooms; 18-28° for the Pink Oyster; and 21-29° for the Yellow Oyster.
* During the next few weeks (it may take up to six or eight), the mycelium threads will invade the substrate. When it’s completely white, remove the tie and open up the bag. This sudden reduction of carbon dioxide levels prompts the mycelium to stop growing and start fruiting. Put the bag back into the container, but leave both the bag and container open. Put the container in a place that ideally is a few degrees cooler than where it was previously stored.
* It’s important to keep the material moist at this point, so spray with water twice a day. Once the pin mushrooms appear, spray only the ‘walls’ of the plastic bag rather than directly on the mushrooms. Growth from pinhead to mature mushroom is rapid - just a few days. Be sure to harvest the mushrooms before the edges of the caps start to turn upwards.
Understanding the mushroom’s life cycle can boost your chances of success. Mushrooms are the reproductive fruits of dense networks of root-like cells known as mycelium. In nature, this root system sprawls wildly in every direction. Once its food supply runs out, or it encounters some other environmental stress, the mycelium enters survival mode: i.e. mushroom production that will enable its spores to be released to the wind and taken to a safer place to live.