Terrarium humidification experiment

August 18 1998

Equipment

Spray bottle
Wet and dry bulb thermometer hygrometer
Perlite
14" x 14" Domed plant terrarium (holds 4 cakes nicely) with a high pointed clear dome perfect for shrooms.

experiment #1

The hygrometer wet bulb reads 66 degrees and the dry bulb reads 60 degrees. (This is a normal room humidity) - 66 degrees on the wet bulb and 66 on the dry would be 100% humidity.

A couple of inches of wet perlite went into the terrarium. The walls of the terrarium were dry and there was no spraying.

The hygrometer was placed on the perlite and the wet bulb crept up to 65 in 5 minutes. 66 on the dry bulb and 65 on the wet bulb means high 90's humidity.

I'm impressed!

experiment #2

This time, just the interior sides of the terrarium were misted. The air inside the terrarium was at ambient room humidity (66 dry bulb and 60 wet bulb) at the outset.

Within 15 minutes the bulbs read 66 dry and 65 wet.

This is not as good as perlite but it shows that fogging mist and droplets on all inner sides of the terrarium will significantly add humidity to the inside air and continue to do so as the fungi transpires CO2 and water vapor while taking in oxygen and water vapor.

experiment #3

All the inside surfaces of the terrarium were misted and one shot of spray mist was delivered into the inside of the dome and mist was trapped as the dome was placed on the top of the bottom tray.

Within 5 minutes the dry bulb was 66 and wet bulb 65 degrees.

This shows how a regular PF dual chambered terrarium with a spray shield can achieve equal results with a perlite terrarium but without the problems of perlite.

Perlite is indeed good but has disadvantages

It becomes smelly very fast (perlite is kind to microbes).
It needs changing and disposing of (messy job) or sterilizing with chemicals (clorox, peroxide ect)

If you think you are growing better now with perlite - it could also be that you are just getting the feel of misting the cakes properly (as lightly as their needs dictate) - or maybe just learning the fungi needs in general.

So in the final outcome; perlite, humidifiers and spray shield PF style terrariums all work. But the last question is, "what is the easiest"? That is my whole game - simplification. What is the simplest? But also consider that in using spores direct to substrate, the fruitings will wildly variate from one to the next. So one try won't tell the story.

Psylocybe Fanaticus
Seattle Washington

Grow Mushrooms from Spores
PF-Tek for Simple Minds