Coffee grounds and some oak wood pellets. Didn't sterilize them either. Just dumped them and chopped up mushroom stems into a half gallon Ball jar.
Discussion
Nice! Pleurotus is so hard core that you probably don't need to sterilize.
Even if it does get contaminated, you'll have experience with the strategy for when you do use a pressure cooker.
If you don't have one yet, "All American" is the best brand to get (it doesn't use a gasket). They're spendy, unless you can find one at an estate sale, or somewhere similar. Next in line is "Presto" brand. I'd only consider other brands if I was desperate.
I have one. I use it all the time. It's one of the big 25 quart versions. I love that thing.
Figured I'd play around and observe what happens if I just use old coffee grounds; see if I pick up some weird mold. So far so good and I'm kinda shocked about that.
Gotta see if I can get these to pin and form mushrooms at all before I go further and start sterilizing stuff. I'm firmly on the event horizon of yet another rabbit hole.
Chances are, if you do get some other species, it won't be weird, but the ubiquitous Trichoderma.
Even if you do get species other than what's desired, it can be interesting to watch the battle.
I had some contaminated petri dishes, and instead of dumping and cleaning, I watched them fight over the next few days. It was a great way to see how they work.
Did one of them win?