Published March 1, 2013. From Cook's Illustrated.
Gardeners might enjoy this mushroom growing kit, but it didn’t quite deliver on its promises.
You can’t get any more local than food you grow yourself on spent coffee grounds. That’s the idea behind this mushroom growing kit, which claims to grow oyster mushrooms in as few as 10 days: Just cut into the cardboard box and spritz the coffee grounds, which are injected with mushroom spawn, with water twice a day. After harvest you can turn over the box and grow a second batch. We placed two kits in the test kitchen away from direct sunlight as advised. After 10 days, the mushrooms had sprouted but remained too small to bother cooking—that is, until one weekend when we left them in a room with a humidifier. By the following Tuesday, the boxes had exploded into big, beautiful mushrooms, though by this point it had been a month since we started. So is it worth it? Only if you enjoy the gardening process, since the kit won’t save you any money: Oyster mushrooms sell for about $12 per pound and our $19.95 kits each yielded two 1/2-pound batches.