Maintaining humidity in DIY fruiting chamber (old school method?)

[TheMooseZeus]

Hi all,

 

I'm building an over the top fruiting chamber for testing environmental parameters on species/ cultivars.

 

So far its a co2 monitor connected to a fan to maintain ~700ppm

 

I'm trying to keep it self contained so have opted not to attach an ultrasonic humidifier.

 

Any suggestions on how I can maintain humidity. Have people had reliable success with perlite or puppy training pads for moisture on the bottom of the tank?

 

I also have an aquarium heater which I can submerge in a glass of water as seen here.

 

I'm a bit unsure on what the heater in water achieves? Temperature or humidity or both? If one parameter reaches ideal conditions and shuts off, I lose the other lol.

 

If I only use it for humidity it could raise my temps through the roof, it gets pretty hot.

 

I'll attach a photo of the chamber in the morning, I have a bag of lions mane almost ready to fruit.

 

Cheers all!

[TheMooseZeus]

I have soaked the puppy pad and it maintains 99% humidity at the level of that sensor, another sensor under the lid drops to %70 after the fan kicks in and slowly builds.

No moisture is accumulating on the walls.

 

[saguaro]

10 hours ago, TheMooseZeus said:

I have soaked the puppy pad and it maintains 99% humidity at the level of that sensor, another sensor under the lid drops to %70 after the fan kicks in and slowly builds.

 

 

 

You'll always have that tradeoff between FAE and humidity when you alter one of those parameters at a time. The best way is to pre-humidify air, but it's way overkill for a small fruiting chamber. 

 

I'm a fan of simple systems, and perlite in the bottom has worked well for me with species like shiitake. For small scale lionsmane growing, cutting the bag they grow from and misting twice a day has always produced results for me. You would have better results fruiting them at a lower temperature than carefully controlling FAE and humidity. 23C is on the extreme end for lionsane.

 

Is it the 'heat tolerant' strain from Rootlab? As far as I can tell the HT strain is not heat tolerant in any way that translates to yielding high quality mushrooms at the temperatures advertised. That said I've been unimpressed by the quality of Rootlab products I've bought in the past, a lot of contamination and old cultures, so I cannot rule out that the HT i bought was just senesced. 

Edited December 17, 2025 by saguaro
clearing up

[TheMooseZeus]

35 minutes ago, saguaro said:

 

You'll always have that tradeoff between FAE and humidity when you alter one of those parameters at a time. The best way is to pre-humidify air, but it's way overkill for a small fruiting chamber. 

 

I'm a fan of simple systems, and perlite in the bottom has worked well for me with species like shiitake. For small scale lionsmane growing, cutting the bag they grow from and misting twice a day has always produced results for me. You would have better results fruiting them at a lower temperature than carefully controlling FAE and humidity. 23C is on the extreme end for lionsane.

 

Is it the 'heat tolerant' strain from Rootlab? As far as I can tell the HT strain is not heat tolerant in any way that translates to yielding high quality mushrooms at the temperatures advertised. That said I've been unimpressed by the quality of Rootlab products I've bought in the past, a lot of contamination and old cultures, so I cannot rule out that the HT i bought was just senesced. 

 

I would typically make a simple system for fruiting any species, I have fruited lions mane in the garage for example. It just doesn't give me the control for testing out environmental parameters.

I got these controllers for free so thought I would put them to use. 

 

I want this system to be able to test fae while keeping humidity stable. Kmart has a $15 usb humidifier that I might plumb into the tub; I can trigger it to turn on after the fans kick in.

 

And it is the HT strain from Rootlabs, so far its grown vigorously on agar and grain. I spoke to a mushroom farmer and he said something similar about the strain. It fruits under higher temps but much better in the cold where it grows denser. I had pink oyster LC from rootlabs and it was very bacterial, they gave me store credit as soon as I contacted them. The lions mane and Reishi I ordered were clean.

 

What has surprised be about this set up is how quickly co2 levels get so high. If I unplug the tub overnight it gets to 4000 - 5000ppm.

 

 

[saguaro]

8 hours ago, TheMooseZeus said:

 

 

What has surprised be about this set up is how quickly co2 levels get so high. If I unplug the tub overnight it gets to 4000 - 5000ppm.

 

 

 

Is the block still colonising? A lot of CO2 is released during colonisation.

 

8 hours ago, TheMooseZeus said:

 

And it is the HT strain from Rootlabs, so far its grown vigorously on agar and grain. I spoke to a mushroom farmer and he said something similar about the strain. It fruits under higher temps but much better in the cold where it grows denser. I had pink oyster LC from rootlabs and it was very bacterial, they gave me store credit as soon as I contacted them. The lions mane and Reishi I ordered were clean.

 

 

Yeah, they have pretty poor quality standards and strain maintenance as far as I've experienced. The Px subculture numbering they use to add value to their liquid cultures is scammy too - what they were calling a P1 culture is the standard you should expect from a supplier, not a selling point to charge 4x for an LC lol. 

[TheMooseZeus]

12 hours ago, saguaro said:

 

Is the block still colonising? A lot of CO2 is released during colonisation.

 

 

Yeah, they have pretty poor quality standards and strain maintenance as far as I've experienced. The Px subculture numbering they use to add value to their liquid cultures is scammy too - what they were calling a P1 culture is the standard you should expect from a supplier, not a selling point to charge 4x for an LC lol. 

Yep, its colonising. I never knew how much of an impact it would have on co2.

 

And I agree, the P number is either a scam or misguided. It's a Paul Stamets 'invention'...

 

 

 

[saguaro]

I agree, P-numbers definitely have value for tracking iterations of subcultures, especially for commercial production.

 

Most suppliers are selling P1 liquid cultures without advertising that as a selling point to command an enormous premium - it's just what customers expect. 

 

 

 

[TheMooseZeus]

I ended up plumbing in a full size humidifier. Hygrometer triggers at 80% and brings it up to 90. Co2 monitor triggers at 900ppm and brings it down the 650.

Humidity stays above 80 for about 3 cycles of the co2 fan triggering.

 

I'll get a bigger box for it in the future. Pics soon