Mushroom Cultivation
Perlite Humidification Technique
See the Perlite Humidification FAQ


A while back there was an interesting post about using a "floor" of wetted perlite as the means to 
create humidity in your growth chamber. It made sense to me because I happened to already be familiar 
with perlite's excellent water uptake/transpiration qualities (the `Rice Krispies' effect).
Anyway, a friend who is growing mushrooms (imagine the audacity!) tried it, and reported excellent 
results. I went and looked for myself, and folks, it was amazing. Basically, you can forget about 
electric humidifiers and all that if you like---this is the low-tech way to go and it works like a 
charm. He had a small PF aquarium bubbler going also, but I could tell that the wet perlite was the 
thing that was REALLY working. The cakes were flushing *beautifully,* MUCH better than I have ever 
seen with the bubbler alone. I could tell that even without the bubbler, it would have still worked 
great.

I assume that what is happening is that the perlite sucks up the water which gravity keeps at the 
bottom of the layer, and through its porous structure evaporates it into the air above the layer, 
doing it very gradually (highly desireable). I guess what makes it work is the fact that perlite 
(unlike its sister vermiculite) doesn't actually absorb and hold water. Apparently though, it takes 
a very long time (weeks is my guess) for the perlite to evaporate the water, so it appears to be 
sufficient humidification for multi-flushing. He had his cakes sitting right on the perlite, and 
where the contact was I imagine there was also wick-like action transferring moisture directly to 
the cakes, which helps.

Once again, it turns out that less is more.