fwiw.....My views on the topic....
The cycle = Spores->agar->rye (grains)->wood chips (hardwood and plant stems mixed)->layered "bag-bin-bed" to full maturation->seasonal change triggered fruiting initiation......
All of the above takes much longer to happen/finish than other species but is well worth the wait IMHO.....(aside from the germination and agar work it's usually fairly fast)
Wood and other ligneous materials from soft punky stems to logs......literally.....plus fertilized potting/top soil.......(I bed things in potting soil and use it like verm)
A basic mix ratio is 2/3 Naturscapes, 1/3 Miracle Grow potting soil......pasteurize the mulch, drip dry overnight, mix together with soil at spawn time (while making a layered bed)
Techniques in the woodlover threads here work well.....
Any enriched substrate, like MM, will have to be sterilized or it will fact allow growth of "other" things......
Still now that you mention it....I bet a nice solid loaf of well colonized MM (allowed to mature in a filter patch bag for example) would make a beauty object for burying in soil and casing with Naturscapes mulch.....might be worth a try....
A bag of Naturscapes, a bag of hardwood smoking chips, and a bag of Miracle Grow potting soil, are the baseline substrate "kit" I like to start with......diversity of materials in substrates is good
But certainly add local broken windfall branches and twigs, many of the "weeds" growing near you, grasses and straws and etc......a light layer of straw in a bed also does wonders....
Mulches, grasses, leaves, soils, and cardboard are all your friends for casing and keeping the bed well hydrated AND breathing..... (no direct sun, shaded well, block wind, keep damp)
Outdoors = very little prep beside hydration (but has it's own challenges, critters, other fungi, bacterial troubles and etc..)
Containers, tubs, bags = made with good clean grain or sawdust spawn, new substrates need pasteurization
Containers, tubs, bags (enriched with bran and etc) = sterilization is required
Once the fungi penetrate the wood and consolidate they will be very resilient ......
Rule of thumb for these substrates IME is damp, fluffy, and with plenty of fresh air......time and patience...
I wish my wood chipper hadn't died.....sigh
Good vibes....
A