VIA LunarHarvest: http://lunarharvest.wordpress.com/2013/02/20/coffee-grinds-to-mushrooms-a-how-to-guide/
Yup. I’m not pulling your leg and I’m not kidding you around; oyster mushrooms (Pleurotus ostreatus) are a species of fungus that can digest coffee grinds, including the filters that they are often discarded with, and produce reliable crops of mushrooms. I was skeptical at first but after doing what seemed to be no more than a month casually searching through online do-it-yourself blogs and investigating companies which distribute mushroom kits and spawn (such as The Mushroom Patch) I had the confidence to give it a shot. I was rewarded with not only beautiful and tasty oyster mushrooms but an acquired set of skills that I can now use to develop further cultivating techniques for this sadly underappreciated crop.
Approximately one month after mixing together the coffee grinds and mycelium together, the oyster mushrooms are well into their first flush.
But why would you want to grow your own mushrooms? The most obvious part of it for me is that you are upcycling, which is the process of converting something that could be interpeted as useless into a new product or something of benifit. You are taking some coffee grinds, which most consider to be ready for the trash, and converting it into edible material. So you are really getting the best bang for your buck; especially since organic good coffee tends to be a little expensive. Might as well use it twice!
Plus you are not just creating any old edible material (Because edible material sounds really appetizing..) but oyster mushrooms, which are delicious and extremely good for you. You can read all about the specifics of nutrition and medicinal properties as well as learn some additional facts about oyster mushrooms here. All of that content could easily be a whole article on it’s own! It’s also pretty enjoyable to be growing a food crop indoors at any time of the year and to be rewarded with what is really, in the long run, minimal effort. Besides the materials and initial effort input it is sort of like just having another houseplant; one that produces something you can eat.
Step 1. Acquiring mycelium and coffee grinds
Chances are, there is a coffee shop near where you live. They are all over the place these days, and so a regular and abundant supply of coffee grinds is pretty easy to come by. My brother used to work at a Second Cup, and he managed to collect 2 garbage bags full of coffee grinds in only 3 days. All it takes is for you to make friends with someone who works at a coffee shop or inquire about it yourself. I have not gone this route since I had a close connection, but I am sure any coffee shop employee you approach will be willing to save some of the grinds for you. Most establishments have to pay to have their garbage dumpsters emptied, so by diverting some of that ‘garbage’ from filling up their bins I am sure they will be more than glad that you are helping them out.
Or, you could save up the coffee grinds yourself. This works well if you live with a whole bunch of people that are all coffee fiends. Pro tip: If you happen to be able to get some organic coffee, then you will naturally produce organic mushrooms. If you are going to go that route and are collecting your own coffee, try using unbleached filters to further improve the purity and quality of your oysters.
As for the mycelium, your only chance is to purchase it online from a company that distributes mushroom spores (referred to as spawn) unless you happen to know someone that you can get some spores from. I ordered mine from The Mushroom Patch and have been impressed with the results. Make sure to follow the instructions on the package to ensure you have healthy and happy spawn!
Step 2: Combining mycelium and coffee grinds
Now all you need is a bucket. It is possible to grow oyster mushrooms in bags