Cultivation Method

Overview

This method of cultivation is suitable for growing Tree Oysters (Pleurotus ostreatus), and Phoenix Oysters (Pleurotus pulmonarius), and it is based on the method described by Paul Stamets in Growing Gourmet and Medicinal Mushrooms. Visit Paul's website at www.fungi.com.

The first step is to find some bales of straw and shred them. Shredding helps a lot when it comes to packing the straw in bags, but it is not completely necessary. After spreading out the straw on a tarp, set up a sprinkler and wet the straw thoroughly. Once the straw is wet, fork it into a vessel of some kind. I use an old 400-gallon stainless steel bulk tank that was once used for milk storage, but almost anything will do. Close the vessel, but not too tightly, you don't want to build up any pressure.

Now, stoke up your steam generator (follow the link for some ideas on how to build one), and start steaming the straw. Bring the temperature (measured with a long-stemmed compost thermometer) up to at least 160 degrees F. (I try to get to 190) for about 2 hours. Do not let the substrate get over 200, though all is not lost if it does (increase your spawning rate if possible).

When steaming is complete, open the vessel and fork out as much material as you can deal with at a time. I fork out about two-thirds of a bale onto a 4' by 8' table. I like to do this when the straw is still very hot, so I then have to spend some time cooling the straw by fluffing it and allowing the air to do its work. This only takes about 4-5 minutes and I think it is better than letting the mass cool for 12-24 hours in the tank, because I can get mycelium growing on the substrate in the shortest possible interval, as opposed to allowing heat-loving contaminants to get a head start during the cooling period.

Once the straw is cooled to about body temperature, it is ready to receive the spawn. The commonly recommended rate of inoculation is 1 bag of spawn (about 5 pounds) to 1 bale of straw, but I use 1 bag to two-thirds of a bale. Anyway, open the bag and distribute the spawn evenly on top of the straw. It is okay to use bare hands, although you should wash them first.

This is my favorite part. The smell of the steamed straw mingled with the fresh scent of pure oyster mycelium is extraordinary.

Now it is time to stuff the bags. (I have used 4 mil plastic ducting like Stamets, which is great because you can see inside, and I have used recycled grain bags, which are free and they work just as well.) This takes some work, as you really need to stuff them, like you would stuff a sleeping bag into a small sack. Try not to allow any excess air spaces in your bag. The outside should be taut and very firm. You cannot get it too tight, unless your bag rips. The mycelium likes it this way; remember, it is used to living inside a log.

Fill it up as much as possible while still giving yourself room to close the bag tightly and seal it with twine, staples, or duct tape.

As soon as you have the bag good and sealed, you need to puncture it with a sharp instrument (I use a 4-bladed hunting arrow) in the places where you want the mushrooms to emerge. This is crucial, because the mycelium needs to breathe. It will suffocate and die if you neglect this step for long.

I poke holes in a 5-6 inch diamond pattern over about two-thirds of the bags surface. A 50 lb. grain bag gets about 25-30 holes.

Now you are done, just put the bag in a cool room, away from direct sunlight, but not in total darkness either. Oyster mushrooms need light or they will malform. The humidity can be fairly low during colonization, but you'll want it up between 80 and 90 percent when mushrooms begin to form.