It took me a couple days to get around to it, but I did eventually take my jars of sterilized coffee grounds and add the oyster mushroom base to them.
I chopped the biggest “root ball” up into pieces and layered those lasagne-style with coffee grounds. The smaller root base I just “planted” with its little leftover mycorrhizae patch in contact with the coffee grounds.
So now I have two little mushroom terrariums.
And we just sit back and watch… and wait. If the coffee grounds start turning white, yay! That’s the oyster mushroom gradually eating the coffee grounds while it grows. If the stuff in the jars gets fuzzy, or blue… well. Not so delicious. Would not recommend for snacks. I wonder which it will be.