I have a regular supply of sawdust from a woodworker's shop, mostly fir, cedar, pine and some hardwoods. I'm aware that many edibles don't do particularly well on conifer substrates but I've also been reading about using coffee grounds. I'm curious whether coffee grounds mixed with the sawdust and sterilized might make a better substrate. Opinions?
I'm mostly interested in oysters, chanterelles and criminis.
By Sawdust I am presuming you mean something with similar consistency to coffee grounds? I've never worked with medium that fine so I can't really speak to that but As for those three species you mentioned. Oyster mushrooms grow very well on alder and I've certainly seen them growing in precomposted compost which is rich with coffee grounds - that's probably the place to start. Chantrells are a complex fungi which grows in association with living trees and to my knowledge no one yet knows how to cultivate them but they do grow in association with conifers and decomposing conifers. Crimini is a later stage decomposer (pretty sure, though I'd defer to someone with more experience with this mushroom) and does well in compost and manure rich sub-straights. I also believe there may be a "Phoenix oyster" which grows with conifers but have never seen it cultivated and don't know its specifications.
Edit: Corrected word 'leaving' to = Living which is what I meant and is more difficult to confuse with 'leafing'
I'll inoculate jars with various combinations of compost, coffee grounds and sawdust and see which does better... if any work at all.
For inoculation, I'm going to try a trick I picked up from making brie. I took a surface cutting from a freshly-opened store-bought brie rind and put it in a jar with sterile water. Then I shook the bejesus out of it, knocking off millions of microscopic mycelial fibers. When that water is sprayed on the surface of the new cheese, it virtually covers the surface with viable mycelia and they cover the cheese in a matter of days. It works well with bleu cheese cultures as well.
I haven't read of this technique being used in home mushroom cultivation yet, but then I've pretty much been away from the hobby for 30 years. I have a lot of catching up to do!
Many use a glass jar blender from the thrift shop. Old oster blenders had standard wide mouth canning jar threads, so you can sterilize the blades and only one jar to make your slurry.
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Okay, so here it is twelve days later and I finally have some results to report.
On Feb. 17th, I made a slurry out of several white store-bought buttons in water and used this to further moisten the pasteurized substrates:
1) Sawdust only
2) Equal parts sawdust and compost
3) Equal parts compost and coffee grounds
4) Equal parts sawdust, compost and coffee grounds
Of the four jars, only the coffee/compost one shows positive results. A light mycelial growth throughout the entire jar except the bottom 3/4", where too much moisture collected. I first barely detected it yesterday, and today it's noticeable from several feet away.
There may be some growth in the coffee/compost/duct jar, but it's had to tell. In any case, I think I can rule out the sawdust as a substrate for buttons. Next I'll try it with blue oysters, since they apparently relish fir trees.
I'll be using this substrate to further inoculate a large plastic bin full of coffee/compost, 2:1.
This is a "before" pic. I'll put up some others once the mycelium show up better in photos.
Have you lightly screwed on the lids?
I made the mistake of sealing my lids (with Oyster mushrooms) and I opened them after a few weeks with an explosive rush of air shooting out, probably from bacterial growth and expiration.
Since I left the lids nearly completely unscrewed, I saw a dramatic burst of growth.
Also, how much water did you mix into the jars? Or, are you spraying them?
In my other post about getting Oysters to fruit, I forgot to mention that I also steam-sterilized my coffee grounds, by putting them in a steamer for 90 minutes in a bowl with tinfoil over top.
I think for the purpose of determining which substrate works best, I would use a conventional method of inoculation. Because otherwise you might never know if it's the method that did not work, or the substrate.