thats a good question, and though im not certain i THINK that most of the mushrooms that grow on materials so composted, they require that the material has quite a lot of fibre, and from my understanding (ive never touched worm castings other than those in the bucket with my canadian nightcrawlers ive purchased for fishing purposes) WC does not have enough fiber
all that being said you can grab spores sometimes from the mushrooms at the store whose veil has yet to break, ones with exposed gills will most likely have dropped all their spores already, to do this you remove the veil with a sterile knife and put them on a piece of printer paper or glass underneath a jar or bowl for 12 to 24 hours and make your own spore syringe with it
but i dont think that white buttons will be the right kind to try with it
i would try oysters because theyre very adaptable, and possibly a poo eater of some kind, there are many poo eaters out there, but the only ones i can ever seem to remember (because i only cultivate oysters so far) are the psilocybes, which you would likely be legally restricted from harvesting a crop from, but a similar, more legal poo eater might be a good idea for you
Although worm castings could be a good substrate for some mushrooms, I've never seen any info about them being used as a substrate for mushroom cultivation. Devon' s right- worm castings are lacking in "fiber".
Collecting spores from supermarket mushrooms is probably not going to work, either. My suggestion is to grow oyster mushrooms from stem butts on wood chips or almond agaricus from purchased spawn on leached cow manure. The numerous threads on this site about oyster cultivation and the books by Paul Stamets can guide you in the right direction. Good luck!
By the way, I've had BIG problems with earthworms in my mushroom projects over the years- earthworms love to eat mushroom spawn such as myceliated sawdust and grain! They can ruin an outdoor spawn run if they are present in your substrate (like compost). But I love earthworms on my farm- I just keep them away from spawn runs, or they'll munch all the spawn!!
i've taken to wrapping mushroom butts into my roommate's used coffee filters and grounds. i've gotten some very nice blooms of mycelia in the worm bin that last weeks at times. the only fungi i can think of that might grow in worm castings would be shaggy manes since they love that high-nutrient environment. you can grow them in large compost piles for sure. the issue is potentially losing the fungi to the worms.
I have seen worm castings as part-but only part of a mix for mushrooms. Other things to put in the substrate were sawdust, twigs, manure, cardboard, wood chips, gypsum, etc. Stamets says that mixed media subrates usually do better than straight uni-mix. It makes sense if you think of evolution. How often have fungi grown in mono crop style in the last million years? Oh right, never.
First you need to figure out how much effort you'd like to put into this project. But Field and Forest is a great source for mushroom spawn for outdoor cultivation. The worm castings aren't great for consistent results in indoor cultivation. Too many unknown variables. You really have no idea of the nutritional content of your compost. But I think if you plan on making an outdoor patch on straw that would be a great addition to your bed. Just purchase already inoculated grain spawn or sawdust spawn for an easy variety of mushrooms and start outside. Don't bother getting any of the books if you are just going to do this for an experiment. Seriously those books do nothing but make you question your ability to grow. Go to youtube and watch some of the videos from other people starting out. This isn't brain surgery but some people make it seem so complicated but it's really nothing more than controlled mold.
People use worm castings in straw or wood substrates all the time. Up to 50% is pretty common. I have in fact seen pictures of mushrooms growing on substrates made completely of worm castings, but the spores werent germinated on the castings. I think the person was using grain spawn.
Spores are more selective about when and where to germinate, but once you have active mycelium you can get it to run through all sorts of things, like oysters growing on substrates made out of crude oil and straw, or psilocybe cubensis running through cigarette butts, if the mycelium has a good nutrient scource it can travel through and colonize all sorts of stuff, as long as its at the right moisture level. It can transfer nutrients from one scource, and through its network of cells transfer nutrients to remote locations within its network so it can spread through and colonize areas and things that are without nutrients in its search for things that are nutritous.
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