Once your jars are 100% colonized you can then open them without it contaminating. So that makes it a perfect time to transfer to its final substrate.
Take your rockhard cowpoo, and run it through a blender, not powder fine but about the density of your MJ soil. Then cut your straw into 2-5in pieces, you can blend it too.
Your going to want to mix before you sterilize so, mix 2-2-1**Poo-Straw-Verm
alot of people pasturize thier final substrate, but i dont like to do all that work/waiting for it to contaminate in one of the final stages so i pressure cook my Poo/Verm/Straw mix in Oven bags(turkey bags)-you can buy them at walmart for cheap, get the small ones, double them up and put your mixed, FIELD CAPACITY substrate in.
Remember when you hydrate your final substrate, squeeze by the handfull until only a few drops of water fall, then put that handful in the oven bag, repeat until your full.
A few tips on the oven bags.
Make sure that the access plastic at the top of the bag can flap around, when you hit the Pressure cooker release you dont want the plastic bag clogging it.
Also make sure that the oven bag doesnt sit in the water, the general heat wont burn the bag but the boiling water will.
You can always do your final substrate in jars too, but you gonna need 3-4 jars of final substrate per jar of colonized corn, thats alot of time at the pc.
You can pasturize by putting your mix in a large cooler and dumping several pots of boiling water on it, let it sit overnight, drain your cooler, bring it in the work area, squeeze to field capacity, then add to tubs for spawning.
When you spawn youll take your fully colonized jars and smack them around a little to break up the corn/mycilium(Spawn) put an inch layer of your final substrate mix then layer your jar of spawn and cover it with another inch of final sub mix.
Walmart sells $1 clear sterilite tubs with lids, like 5 liter i think, those work great, you can stack 10 tubs in a black trash bag in your closet and nobody would ever think anything of it. you can also use Tin Baking pans.
Take into consideration your fruiting chamber tub and your spawn tubs at the same time, it sux to end up with 8 colonized spawn tubs and a fruiting chamber that only holds 5. Remember though, your not going to be stacking spawn tubs in your fruiting tub, its side by side space your needing.