Growing Oyster Mushrooms in Coffee Grounds

Oyster mushrooms growing in coffee grounds photo

Mushroom Kit for Gardenless Gardening
I’ve posted before on Paul Stamets’ TED talk about mushrooms saving the world, and have covered resources like and 100 Edible Mushrooms. In short, I’m mildly obsessed with the fungal kingdom – reading anything I can get my hands on right now. My latest shroomy-escapade, however, has been purely in the realms of the practical, and would make a great gardening project, even for those with no access to land. I’ve been using old coffee grounds to cultivate delicious oyster mushrooms. Here’s how…

I purchased a kit from Fungi Perfecti (Stamets’ company) known as the Espresso Oyster mushroom patch. The kit consists of inoculated grain spawn, which arrives covered in a white, web-like mycelium. You then mix this with a bucket of coffee grounds from your local coffee shop (because the grounds will have been steamed already, this cuts out the need for sterilizing the growing medium). Then you basically wait – spraying the medium occasionally, and covering it with perforated plastic to keep moisture in. I’ve had mine about two months, and am now enjoying a flush of fruitings.

A couple of things I have learned on the way, which aren't necessarily covered in the kit instructions. If the surface of the coffee grounds is way below the rim of the bucket, it can be good to drill air holes around the rim nearer the surface – CO2 is heavier than oxygen and can build up, causing the shrooms to grow long and stalk-like. Not very appetizing. Similarly, it’s worth making sure the shrooms get enough light – otherwise they may also develop weird growing habits. And finally, try not to water them too much – the instructions that came with the packet said mist daily, but I have had some problems with mold growing at this kind of frequency. When I cut back on the spraying, and moved the bucket outside to cooler temperatures, mold growth disappeared.

And that’s it – it really is a super easy introduction to the art of mushroom growing. And if you treat your kit carefully you can even transfer the mycelium into new substrates – extending its life and getting even more mushrooms for your money. You can apparently also reproduce the mycelium by placing putting stem butts between moistened and torn sheets of corrugated cardboard - though I'm working on this one. And once the substrate is completely spent, it makes for an excellent addition to your garden compost, assuming you have a garden. Now, if you’ll excuse me – it’s my turn to cook.

Fungi Perfecti - With thanks to Christian "Critter" Olsen at Fungi Perfecti for the excellent advice and customer service!

More on TreeHugger about Fungi and Mushrooms
Paul Stamets at TED: How Mushrooms Can Help Save the World Online Guide to Mushrooms and Fungi
Hair and ‘Shrooms to Clean Beaches
Adding Fungi Can Boost Ethanol Production
Shrooms to Grow: Home-Grown Insulation Gets Fungi
Can Mushrooms Lubricate Your Chainsaw, Feed Your Dog and Save the World?

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