Agaricus campestris

Is anyone growing meadow mushrooms? I can't seem to find any detailed instructions.

Meadow mushrooms are bullshit.  Actually, recycled bullshit since the species has evolved to break down herbivore patties that have been deposited in the wide open spaces.  The species in the genus are probably very similar in their growth requirements, so you could use recipes for culturing Agaricus bisporus and see how that works for you.   It would be helpful to have a cow or a horse to provide you with a steady supply of growth media.

I had quite a few in my yard for several years. They were just in the grass, no manure or compost. I don't think there was even much organic matter. I'm sure they'd do better with manure.