This is a pretty spontaneous post to be perfectly honest, as I unexpectedly happened upon some reasonably freshly cut straw in the forest near where I live. There wasn’t a lot, but definitely enough to do some experimenting with, and it was dumped in neat piles right along the side of the trail that I was walking; it’s bright yellow brown color standing out like a glowing beacon against all of the brown, gray and flecks of green of the still mostly bare woodland. Straw, most often derived from wheat, barley, or other agricultural grain species, is the most common substrate from which commercial oyster mushroom (Pleurotus spp.) are produced, in addition to a few other minor ingredients including moisture retaining minerals and nutritional supplements.
My thought is that any kind of straw, whether or not it is derived from agricultural grains, would perform at least satisfactorily for oyster mushroom production. The straw that I have collected is most likely from some species of ornamental grass, that is unless someone happens to be growing a little patch of wheat or barley in their yard. Not really worth it if you ask me. The single mini loaf of bread that you could make from all that grain would be pretty damn tasty though, and highly coveted I’m sure.
Anyhow, I thought I would experiment in this regard and I’ll let you know what my results are. I am going to stick with the same basic materials and methods that I have always used for this experiment including my latest modification which, in case you missed it, was stretching a porous material over the opening of the mason jar so that there was better and more consistent air exchange. This time, I am also going to sterilize a translucent plastic tupperware lid to place over the mason jar so that it can breath but is not directly exposed to contaminants in the open air of the room. I will briefly lift up this lid once a day and fan the jar, allowing fresh air to displace the stale air, and then place the lid back over top. I’ll also mist the inside of the tupperware to keep the conditions in the jar’s micro-habitat nice and humid. Below is the rest of my process, step by step.
* if your straw is in long pieces, cut them into short lengths so that they can fit more easily into your chosen starter container. If straw is moldy or has visible signs of advanced decay, do not use it. Freshly dried straw is the best to use.
1) Place desired amount of straw into a bowl, bucket or pail (whatever container is best suited to the amount of straw you are sterilizing).
2) Pour freshly boiled water over the straw until the straw begins to float to the top of the water.
3) Gently stir around and mash the straw briefly with an appropriately sized, clean utensil.
4) Let the straw sit in the boiled water until the water has cooled. This steeping will rehydrate the straw, which is necessary for the mycelium to grow.
5) Take out the straw from your container using a cleaned set of tongs etc. and allow to drain on a clean surface.
6) Pack the straw tightly into your clean, sterilized starter container halfway.
7) Place oyster mushroom stem cutting into the first layer of straw.
8) Cover the stem cutting with more straw, packing down only lightly, until it reaches the top of the container.
9) Place clean cheese cloth over the top of the jar and secure with an elastic band.
10) Relocate jar to a good location for incubation and then cover with a cleaned, sterilized tupperware container.
11) Mist the inside of the tupperware container as needed and remove the lid for air circulation daily.
12) When all of the straw has been fully colonized, this starter can be used to colonize a larger batch of substrate for the purpose of fruiting.