I started them as "set and forget" but then realized the plastic bag lining is above the CO2 holes, so I trimmed it and started venting once every day. There is lot of humidity and even water droplets on the mycelium, so I thought maybe more fanning is needed to promote evaporation.

Another issue were the low temperatures. The weather got warmer just two days ago and I placed in a room heater just to keep the night temperatures above 19° C (66° F). Unfortunately last few years we have sharp temperature changes - going from freezing days to almost full blown spring in just 4 days. It's crazy.

So maybe they don't grow due to high CO2 levels or low temperature or both.

Another problem might be a bad vermiculite. I use fine grained one but I found a tek saying repeatedly than one has to use coarse grained. Not sure why. The mycelium seems to grow well in both (I tried medium and fine vermiculite in BRF cakes in the past and both work the same).

Yet another issue might be the manure pellets. They come pre-pasteurised so maybe pasteurizing the substrate will over sterilise it. I will experiment with different verm and manure to see any changes.

Now there is enough air exchange, heat (but not too much) and 12 hour lighting from 24W 6500K fluorescent tube (worked great for PF cakes).

The mushroom solitaire seems to be a great indicator of fruiting condition though I don't know if I should consider this a "flush" and soak the monotub after picking that one or just wait for larger flush.

I would wait. How long has it been fully colonized?

I've heard some folks say they scratch the mycelium with a clean fork to promote pinning if fruits don't show up, but I've found that waiting works.

It's fully colonized for about 10 days or so. The colonization took over week longer than usual probably due to colder environment. I observed the mycelium was eating some of the straw that was protruding from the substrate, but now it seems everything is covered by the white goodness and stable. I've read mushrooms won't fruit until there is something to eat - they focus on growing myc and when there is no more nutrition, they start focusing on reproduction.

Yes I will wait and report then.

Next time I will try placing wax paper on top of the substrate at around 60% colonization. This is said to create a micro-clima for more pins to form.

Thanks for all you help so far

Okay so few pins finally appeared in the first tub, the second is still inconclusive.

Here is the one brave guy, doing well. He's fat indicating O2 levels are high, so venting was not needed at all.