The Shotgun Terrarium
The Shotgun Terrarium is an easy to make and easy to maintain fruiting chamber. It has no moving parts, needs no electricity and does away with shields and other complications.
How does it work?
The principle behind the shotgun terrarium is that of using perlite to increase air humidity. This is by no means an innovation as before the shotgun terrarium was developed it was already used. Here is a closeup picture of a piece of perlite. Notice how perlite is covered with ridges and bumps. Once you wet your
perlite, this increases the surface area of water exposed to the air
thus dramatically increasing evaporation rates over the same volume of
water on its own. More evaporation means higher humidity.
Building a Shotgun Terrarium
You will need:
- A transparent/translucent plastic storage container. The lid does not have to be transparent but if you have the choice, go with the transparent top. Mushrooms grow towards the light and if they get no light at the top they will grow sideways.
- Electric drill with a 1/4 inch drill bit
- Perlite. Enough to fill 3-5 inches of the bottom of the container.
- Pasta strainer or similar.
Step 1 - Drill the holes
Drill holes in all six sides of the container. Space them out evenly, with about two inches between holes. Now you know why it is called a shotgun terrarium :D
Step 2 - Prepare your perlite
Fill your strainer with perlite and wash it thoroughly under the tap. This both cleans the perlite of any dust and covers all the surfaces with water. Drain the perlite well.
Step 3 - Place perlite in the fruiting chamber
Fill up your terrarium with the moist perlite. It should fill
3 to 5 inches of the bottom of the container. Spread it out evenly, keeping it as light and fluffy as possible. Your fruiting chamber is now ready.
Step 4 - Put your cakes into the fruiting chamber
It is now time to put your fully colonized cakes into the terrarium and put the lid on. Do not place them directly on the perlite. Use old jar lids or pieces of tin foil as coasters to avoid direct contact.
Now, all you have to do is open up the lid twice a day and fan some fresh air into the fruiting chamber. You can use the actual lid of the terrarium as long as you keep it clean. We do this to introduce extra fresh air into the chamber.
While a lot of fresh air gets in through the holes you can never really have enough fresh air (as long as the humidity stays in the high 90%s) as it is a very important pinning trigger and also hinders the growth of contaminant molds. Before fanning (30 seconds is enough) give the cakes a good thorough mist with your water mister to keep them nice and hydrated.
Extra Tips & Tricks
- Use a hygrometer to measure the humidity inside your fruiting chamber. It should be as close to 100% as possible. If on its own this terrarium does not achieve over 95% relative humidity, tape up some of the holes to slow down air exchange and that should increase your humidity levels.
- Expose your terrarium to light for at least a few hours each day. Light shows the mushrooms which way to grow and ensures even and prolific pinning (if all other conditions are correct). Indirect sunlight is good (avoid direct sunlight) or if you can't have it, use a compact fluorescent (energy saving bulb) or standard fluorescent bulb that gives off light in the daylight range. The packaging will say something like daylight or white light or 6000K (somewhere around that number). Good results have been obtained with a 12 hour on 12 hour off cycle. Stay away from incandescent (regular) lightbulbs as they do not emmit the right kind of light and produce a lot of heat
- Keep your terrarium slightly elevated. Use a couple of bricks or something to elevate the terrarium off the floor. This keeps it away from the dust and muck on the floor and more importantly lets air go through the holes you have drilled on the bottom.
- Here is a video describing the process and also another document describing the science behind the shotgun terrarium in greater depth. This site has also got some great videos explaining many other procedures, including the PF Tek.
Nibin 2009. Special thanks to RogerRabbit for letting me use his pictures and video.
