In my last blog I briefly discussed my recent (successful) attempts to cultivate Ostreatus pleurotus, the lovely Pearl Oyster Mushroom. (These come in a variety of colors, but the one I've attempted is the most common, the pearl-grayish-white color of the prolific Pearl Oyster.)
The method I spoke of was using 3-foot lengths of cut maple lots, about 5 or 6 inches in diameter, with mycelium-impregnated spawn plugs (commercially available) hammered into quarter-inch, inch-deep holes drilled into the log, then sealed with wax. The log is then mounted on a tripod-like mount (which I made of outdoor wood) about 18" tall, which keeps the log off the ground. This method produces fruitings typically in the spring or fall, and supposedly can continue for many years. The entire apparatus is depicted at left, and you can see some of the plugs fruiting.
In my opinion it's pretty hard to fail in cultivating Oysters using either method, fast or slow, since they are so hardy and grow in such a wide range of media. This article in the Huffington Post (which I'll discuss in more detail in tomorrow's blog) says: "They grow readily on dead wood, straw, grasses (wheat, rye, rice, fescues, corn, bamboo), cotton, cacti, Scotch broom, hemp, coffee wastes, paper products, and practically any other dried cellulosic plant material."
But first you have to prepare a mycelium culture with which to impregnate your growing medium. The fast method (which I attempted before settling on the slow method, for reasons I described in my last blog) involves boiling strips of cardboard to sterilize and moisten them, then after it cools sufficiently, pulling it apart and layering (using a flame sterilized knife) slices of Oyster Mushrooms between the layers. (Since I really like to eat the caps, I use the less desirable stem portions for this purpose.)
I sealed my Oyster nurseries in Mason jars with coffee filters replacing the lids (for airflow), and let these rest at room temperature in a dark place for about a week. If the top of the culture looked at all like it was drying out, I would remove the lid and remoisten it with a spritz or two of distilled water.
After several days' time you should see the hair-like, white, cottony Ostreatus pleurotus mycelium spreading all throughout the cardboard. If you see green (indicating mold), it's most likely ruined and you can throw it out. But in 80 or 90% of the cases I tried, the pleurotus grew in sufficient quantities to overwhelm any mold culture that might have snuck in there. (If you are really serious about mushroom cultivation, you can install in your working space a sterilizing air filter that removes mold spores from the air where you are working. But that's a little too fancy for my purposes.)
The next step is to don sterile gloves and stuff plastic bags (which you can purchase sterilized and pre-prepared for the purpose) full of sterilized straw, then carefully remove and insert several of the mycelium-impregnated strips into each straw bag. Close its open end with a zip-tie.
These bags can be hung in a dark place, once again at room temperature. In another week you should see the mycelium begin to take over the straw with its fuzzy whiteness.
If you use bags purchased for the purpose, as I did with the bag depicted at right, they will have perforations which allow for the Oyster Mushrooms to fruit out when the organism is ready. Once you see that your pleurotus mycelium has taken hold (once again, watch out for green mold, which will spoil the batch), you can start "stressing" the organism to cause it to fruit rapidly.
To do this, move it near a natural light source, like in front of a window. Also make sure there is plenty of ambient moisture (humidity) in the environment. I hung my straw bags from a length of cord attached to a ceiling hook, over open pans of distilled water, then "tented" around the straw logs with plastic sheeting to hold the moisture in and keep bugs out. (Although Oyster Mushrooms are not at all susceptible to insect infestations and have many healthy, natural anti-insect and anti-bacterial properties, as you will read in the aforementioned Huffington Post article.)
Within days your straw logs should be fruiting wildly, and you can cut mushrooms when they look at their peak of readiness. After cutting, return the bag to its dark closet for a few days, letting the mycelium recover a bit, then re-introduce it to light and moisture to encourage a second fruiting.
Sometimes, using this method, you can even achieve a third fruiting before the medium in the bag is fully expended.
Afterward, you can of course recycle the straw into mulch, as well as the plastic bag (if you are using the right kind of bag!) In the photo below, the bag at right is older than the bag at left, and you can see it is completely filled with white mycelium. That particular bag was done fruiting, though I left it hanging for awhile just to be sure.
Speaking of health, I wanted to make mention of two potential health hazards here. First off, remember that you should always cook Oyster Mushrooms and not eat them raw. I've read that they contain some sort of toxin which some people may be sensitive to in quantity, which is boiled off when the mushroom is cooked at at least 140 degrees F, as it should be.
Second, I mentioned in my last blog how we discovered that "Mushroom Worker's Lung" is a real thing with Oyster mushrooms. Some people are allergic to the airborne spores (my wife is, I am not). These cause flu-like symptoms of respiratory distress. The problem can be alleviated by using a filter mask capable of filtering out objects at least 3 microns in size (as Oyster Mushroom spores are typically 8-10.5 x 3-3.5 µ), or by avoiding indoors areas where Oyster Mushrooms are fruiting. I haven't heard of anyone (my wife included) experiencing problems in outdoor areas where they are fruiting (like my back yard).
Now that you know how to grow your own Oysters, in my next blog I'd like to tackle WHY you should do this! The Oyster Mushroom is one of the most amazing of God's creations, and we will discuss some of the reasons why. So, stay tuned!