A lab in the dark
Foraging for mushrooms can be perilous, but a sustainable food production venture has launched growing kits to help you harvest oyster mushrooms at home
Oyster mushrooms being grown by Andrew Douglas of Dublin’s Urban Farm and Mushroom City in Dublin. Photograph: Richard Johnston
If you’ve ever gone foraging for wild mushrooms, then you might agree with me when I say that it’s an experience loaded with more than just the occasional frisson of danger. Surely I’m not the only craven person who, faced with the chances of confusing a tasty edible variety with one that’s hallucinogenic or deadly poisonous, soon comes to the conclusion that acute liver failure is, ahem, perhaps a risk not worth taking. Growing your own mushrooms, on the other hand, sounds a far safer bet.
If a new venture on the part of Andrew Douglas, the brains behind the Urban Farm roof garden project in the heart of Dublin city centre, comes to fruit, then that’s exactly what many of the nation’s gardeners will be doing this autumn. High up above the city, in the upper storeys of the building known as the Chocolate Factory, is Douglas’s make-shift but futuristic-looking laboratory where for the last year or so he has been experimenting with different food growing projects as part of his interest in sustainable urban food production.
Next to the trays of leafy greens growing under artificial lights and the bubbling fish tanks filled with trout and goldfish (all part of the Urban Farm’s trial aquaponic systems where the nitrogen-rich water from the fish tanks feeds hydroponically-grown plants), is what looks like a rather swanky, silver tent. A self-confessed science boffin, Douglas jokingly calls this his “mushroom inoculation chamber” but in fact it’s what’s known as a grow tent, of the type particularly popular with “purveyors of illegal drugs”. Except that there are no cannabis plants inside this one, but instead some small plastic wrapped bricks out of which oyster mushrooms are growing, their golden, shell-like caps gracefully erupting from small slits in the packaging.
Closer examination reveals that the bricks are made of tightly-packed coffee grinds mixed with a little damp cardboard or paper pulp, which Douglas says is the perfect growing medium for these fungi (other suitable materials include sawdust or even a dampened loo roll, or paperback book). Once inoculated with the mushroom spawn, covered with plastic, and kept in a warm place, the grinds gradually become colonised with the fungal mycelium (the pale-thread-like precursor to the actual mushroom). These mycelium are eventually followed by the ‘pins’ or baby mushrooms, which within a few days will grow to full size.
As a relatively safe and easy way to grow a food crop, it makes a lot of sense. All the more so when you consider the cost of oyster mushrooms (anywhere from €12-€24/kg) in shops and the food miles embedded in them. Add to that the fact that coffee grinds are a by-product of the catering industry – every year, the world produces an estimated 12 million tons as a waste product – and you can understand why Douglas is enthusiastic about the possibilities of home mushroom-growing as a sustainable food crop.