My 6th monotub attemp seems to fail again. The mycelium always colonizes the bulk substrate almost completely and then stalls.

The substrate is coir, verm, horse poo, peat moss and some gypsum.

The grain was inoculated from LC on 12/14, spawned on 1/5 and placed in fruiting chamber on 1/12.

The temparature is around 20 C (68 F) with constant 90-95% RH. The substrate now seems to be consolidating, there were lots of rhizomorphic growth but a cotton-like plaque appeared during the last weeek. It does not smell bad, there is a mushroom smell but it is weak and somewhat stale smell making me afraid there is some mould present.

I am afraid there is a mould contamination though it looked perfect and fully colonized two weeks ago.

I am not sure what am I doing wrong. Maybe spawning to pasteurized substrate in the kitchen is a bad idea and more sterile conditions are needed? Or maybe too little hpoo? Too much hpoo?

The white bit of the substrate is fine. The bit of yellow to the right of the image might be concerning, but it wouldn't cause the whole tray to stall. The white cottony will pull together to form pins, in fact I see some.

The temp is a little cool, but it should still fruit. Albeit more slowly.

You might have issues with fresh air exchange. What is the setup of your fruiting chamber like?

Regardless of all the parameters cubensis should still fruit anyway when all the substrate is colonised.

That tray looks just fine to me. It looks fully colonized and nine days is not too long to wait for pins.

The yellow liquid you are seeing is just mushroom metabolite and it's normal to see a small amount. You can dab it away gently with a clean dry paper towel.

Keep doing what you're doing and don't forget to give it fresh air 3-5 times a day, and you will hopefully see pins soon!

Spawning in the kitchen is fine as long as you don't have a garbage can full of rotting food right next to it. It's always a good idea to clean up, wipe down surfaces, and maybe turn off your A/C or heat before getting started so they aren't blowing contaminants around.

Thanks for the info guys.



I can turn on a large heat pad below the monotub, controlled by a thermostat.

People told me heating is unnecessary and can promote drying, so I turned it off. But maybe it's better to heat it a little.



Unfortunately I don't have so much time, so I adopted the "set and forget" style people have with monotubs. That's one reason I am switching to monotubs - no need to harvest cakes every other day, just one big flush once in a while.

The mini-monotubs are placed in a bigger plastic tray, having 4 larger holes (approx 4 cm diameter) covered with micropore tape and many small holes (approx 6 mm diameter) on the bottom as a CO2 outlet. The bigger tray will be used as a monotub after the small ones will prove themselves working.

There is 6500K fluorescent tube on a 12/12 regime.



Yes. I use 10% bleach solution and the substrate containers where wiped with IPA.

Patience... You might be surprised to see little mushrooms popping up any day now. Your sub looks pretty good maybe a little more fresh air but otherwise I would just wait!

Sweet! Which IPA did you use? Founders? Lagunitas? Dogfish Head?

Sorry, couldn't help myself.

It sounds like you're doing everything right, but I would still give it the occasional manual fanning. If your humidity is that high it can't hurt. I'd bet that the micropore tape you're using is great for keeping out any contamination but probably doesn't let much fresh air in. I'm not for sure though, I've never actually used it. I do know that the CO2 will have a hard time leaving if there isn't much air coming in.

Yeah, people told you right mate. If you are in a cool place you can heat the air in the room, but NOT place a heating pad under the substrate. 22c is optimal iirc.


Yeah, it looks like it will come along okay.


Is this a new tek/design? When I have made monos/mini monos I always spawn straight into the fruiting chamber. There are 2 holes on each of the long sides, right at the substrate line and 1 on each of the short sides up high. They then are stuffed with polyfil or covered with compressed polyfil. The bottom one's are tighter than the top ones. Creates a mini greenhouse and the air is exchanged from top to bottom, so the carbon dioxide is sucked out right off the substrate surface and the fresh air flow is slow but constant.


This an enzyme that the myc uses to fight infections. Mushroom antibody if you will. So it's good to keep an eye on it if it's pooling in one particular area.

Okay this is the part I don't understand: Why bother will all the disinfection, polyfill and filters at all, when we basically crack open the monotub several times a day, fanning it with dirty air?

I will replace the micropore with some loose filter (time to destroy a pillow). The micropore tape seems to restrict airflow as I see with my stalled jars. I tried to avoid polyfill as its bulky and traps water droplets.



Unfortunately the room with mushrooms is the same one where I store volatile chemicals, including DCM, so I try to avoid larger heat sources there.

Maybe 22c is still okay. I will look for a cheap heater that will sit on the other side of the room. It's just a tiny storage room so heating it should be fine...

I can see how using filters will reduce the exposure to the air in your room. If you really wanted to protect your tubs you could even spawn them in a sterile environment. A well-pasteurized substrate doesn't need all that protection though, and a fully colonized one definitely doesn't.

When I used tubs with polyfil, it was more about automation of the type you're getting dialed in. Even when I was using polyfil, though, I still had a fan running on a timer a few times a day to promote air exchange.

And don't destroy your pillows! Especially if you are concerned about cleanliness, get a new bag of polyfil. Pillows are full of mites and skin flakes.

I agree with what Sidestreet said above in quote, especially the last 2 sentences there.


Also I agree with Northerner, 68F is a bit cool. Mines always been between 72-76F. I use a pillar-style electric heater, set the room temp, it reads the room temp and goes on/off depending. Never had issues. Not saying you can't do things at 68F but I'd imagine it's going to slow down a bit when things are done around that temp. 22c should do alright.

If it was me though personally I'd try to keep the temperature around 73-76F. Probably just my own personal preference, but that temperature range has never failed me - bulk, pf jars, etc [in terms of speed, pin formation, and fruiting].

Looks fine to me! The long fruiting time is probably due to your colder temps, I grow within the same range and it takes a little longer than in the summer. I have found a casing layer helps a lot during the cold/dry seasons. Also have found that in the winter you might have to list and fan a lot more (used to never do this at all) in order to initiate a pin set. The reason that we wipe the tub down with ipa before spawning is because before it reaches full colonization, the bulk sub is vulnerable to competitor fungi, but once the p.cube myc takes hold it has its own defenses against contaminants.

I see, thanks. It makes sense.

So the tub just started fruiting I took about 10 days more than it "should" but that's, as you say, probably due to colder weather.

Pics! Pics!!

Here you go

Booya! Just needed a bit of time

Lookin good so far

<rubs hands in anticipation>

That monster on the side in the last pic...

Looks good, bit why two blocks? The entire tub should be filled with substrate for what I understand as a monotub.

Because these are one of several experimental mini monotubs. I made six such mini tubs in total to find a working recipe for the large monotub.

All this hassle with mini monotubs is because I have only compressed horse manure pellets and don't know how to translate pellet weight to real horse manure weight (I can't find any reliable recipe for pellets - everyone refers to either US or UK-specific brands or plain dried manure).

...so I have to experiment with tiny boxes - better lose few tiny ones than a big one.

Ok I think I got it.

The way the individual containers look in post #1 there may be pooling of the heavier CO2. Did you poker holes at the mycelium line to avoid this? If not the different gas flow vs classic monotub will skew your experiments. Then in the last picks the blocks look like they are outside of the individual containers (birthed) so they would be getting the typical passive air exchange from the monotub double row holes.

Did you notice a shift in behaviour after birthing?

I hope I'm interpreting the pictures correctly, otherwise I won't be making any sense.

Also, the composted cow manure in many recipes comes with typically 35% water weight. That should allow to "translate" the recipes to your case. I'm curious if the experiments would support that.