For my first grow I've decided that I'm going to try the unmodified tub method that I've been reading more and more about recently. It seems to be very easy and relatively high yielding. I inoculated my grain bags last week and I'm just waiting for them to fully colonize, then I'll mix it in with my bulk substrate (coco coir/vermiculite) in my 60L/64qt sterilite tub.
I won't be modifying the tub at all. No holes or polyfil or anything. I plan to leave the lid on until the substrate is fully colonized and then when its ready to fruit I'll open the lid and flip it over place it back on top of the tub with a small gap for fresh air exchange, expose the tub to light and begin misting a few times daily. I'll be closing the lid at night.

I'd like to hear if anybody has any experience with this particular method, and the pros/cons of this vs. A regular mono-tub. I'm also not sure if I should use a casing layer on top of my substrate. Any advice is appreciated!

I would be worried of stalling the tub colonization due to too much CO2 pooling at the bottom, especially for the higher bulk/spawn ratio. What ratio are you planning on? With a small ratio there may be enough O2, but I would expect increasing issues with increasing ratio (I don't expect this to work of at 50% for example, but I could be wrong).

I bought bags of sterilized/hydrated grain that are 3lbs each. I was told to use 2 bags of grain spawn to 10lbs of coco/verm mixture at field capacity. And that should give me roughly 4 inches of substrate in the bottom of my tub. I was also told recently that the tubs still get a tiny bit of air even with the lid latched on because the seals arent perfect.

Ok, so you will have 60% bulk substrate. I would be concerned with stalling.

Remember that CO2 being heavier than air will pool at the bottom of the tub. The lighter O2 will be displaced towards the top. Without holes at the bottom of the tub to let the heavier CO2 out, you should get CO2 accumulation even if the lid is not completely airtight.

If you decide to proceed it would be interesting to see what you get.

https://www.shroomery.or...flat.php/Number/22337800
Are you refering to this tek @juremaSpaceship? I guess everything you need to know is in that link and the pictures speak for themselves

@loveall while what you are saying seems logical but for some reason (maybe mentioned in the link) unmodified tubs work quite well and there's no concern about the CO2 accumulation

I have read through that one quickly.

https://www.youtube.com/...v=kc75VWsrnbM&sns=em
This video is where I got the idea from. He sells the sterilized grain that I bought.

I'm confused by his repeated statement of "you don't have to do this in a sterile environment". You should always be as sterile as possible when mixing your grain with your sub. What he's explaining has a high likelihood of contamination.

Unless there's a new technique that I'm completely unfamiliar with.

When the spawn is "fully" colonized it becomes almost immune to contamination, contamination will definitly happen if any of the exposed grain is not colonized, mold will strike there.. of course after some weeks and as the mycelium gets old it might contam. When you fruit you are basically exposing your cake to open air which is full of all sorts of contaminants, you might as well put your hand there, won't make a difference.

right... but i'm talking about before you get there - i've always been told (and done) if the tub isn't clean, at least wiped down with diluted bleach or ISO you're at much higher risk for contamination. Additionally in the video he recommends mixing the grain and sub with your hand, and again states that you don't have to worry about contamination. Tho he does recommend washing your hand, still.

I'm all for cutting out steps, what's stated in the video is just the exact opposite of what I was taught and what i've seen published and accepted by the masses.

Well you only open the bag when it's fully colonized after that everything is far from being sterile, the gloves the air and even the substrate is not sterile. And sure one should clean hands and clean the tub and be as clean as possible but is it really a "much higher" risk or just being cautious. What i'm sure of is that it's fine to use your hands even if they are not super clean.
A simple way to look at it is, they're being exposed to air!

It should work just fine but you might have to fan a LOT! FAE is so important