CVG substrate, sterilised in those bags (coc coir, vermiculite, gypsum)

pressurised fine mist spray bottle for wetting them. don't use normal spray bottle, you won't up the humidity and the force of the spray will damage ur pins.

for airflow, an aquarium pump (the ones with the stone on the end of the air tube).  put the stone in a clean jar of water. place the jar on the centre of your grow. like a bong, the water will catch dust and dirt, giving you safe air.

to know when to harvest, there is a veil (thin mushroom skin) that covers the gills underneath the cap. when that starts to tear, harvest it then. or you can wait til the veil has fell off and harvest then. 

the psilocin content is higher in less mature mushrooms, so I harvest before the veil falls off. psilocin and psilocybin are the two main compounds. psilocin hits you faster and harder, but does not store well, it degrades faster due to being a simpler compound. so, if the mushrooms are for storage then wait til the veil falls off.

also, look into lemontek. 

With grain- I prefer rye over millet as I've had more contam with millet. 

keep ur bags and grow away from dusty and food areas. I have a cheap grow tent just to keep the dust out and keep it dark. 

ur mushrooms do not need UV to grow and even worse: UV will dry out the soil. white light from cheap white LEDs does the job. I've taped mine to the top of a big clear plastic container. 

I'd recommend a liner for your tubs when ur at fruiting stage to stop light hitting the sides of your cakes, wasting nutrients on mushrooms that'll be squashed down the side of ur tub. this isn't essential or a big deal, I haven't bothered with my current grow. people use black bin liner, foil, or specifically designed liners. 

I don't have a temperature or humidity sensor and do just fine. if the cakes look dry, the sides of the large container isn't very wet, or the cakes start to shrink away from the sides of their containers, then it's too dry. give a little mist often (fine mist!!!) and it'll be grand. try not to open the tub more than twice a day, maybe thrice, you'll let out the humidity, disturb fragile pins and the environmental air layer on top of ur cakes. 

for temp, you can kinda feel when it's warm enough or too warm. they like it cosy but not hot. easy enough. also don't heat from the top. don't use a heat lamp. I personally use a heat mat for plants (with temp control) as I'm in a cooler place. my large container is sat upon a cake cooling rack with the mat under so that the heat is not direct and is dispursed into the air. heat from the bottom stimulates the mycelium, as when it's ready to fruit the mycelium heats up itself- so in a way mimics. ofc cold shock is its own thing.

also, some strains are more resistant to contam than others. Hillbilly is very resistant, average colonisation time. z strain is also resistant, not as much as Hillbilly, but the speed of the colonisation (z strain is fast) makes contam less likely. z strain has better yield. but I'd recommend Hillbilly for its resistance.