This TEK is a modified version of the PF-TEK, like found on PF-Tek for Simple Minds | Fungifun . A lot of the information here is the same as in the PF-TEK, but it's convenient to have it all in one place. I don’t take credit for any of the information found here, I’ve found everything on the above website or the Shroomery and put it together here.
There is a reason companies selling 'magic mushroom grow kits' or 'mycelium boxes' have been doing it like they do. It is seriously easy to do, it is hard to screw up, and yields are good.
This method is not for people willing to invest serious time in their growing hobby, creating a sterile environment, nice fruiting chambers etc. This is just the easiest way to grow mushrooms.
This TEK is designed for Psilocybe cubensis mushrooms, but I think it will work with every mushroom that can be cultivated on brown rice flour.
When I started using mushrooms a few years ago, they were still legal here so we could buy them in the smart shop. 15 euro's for a trip (30 grams fresh) was way overpriced though, and I soon discovered that I could buy pre-made grow kits. These grow kits are made of filter boxes filled with cubensis spawn, and come with a filter bag to fruit in. They cost about 30/35 euros and yielded 400/500 grams fresh. A very big improvement over just buying the shrooms. 
After a while I realized that these grow kits were still overpriced and I wanted to grow my own shrooms from scratch. Also grow kits are illegal in a lot of countries.
I looked around on the internet and, of course, I decided that the PF-TEK would be the best way for a beginner to grow mushrooms. I followed the PF-TEK a few times but kept running into some problems:
- When using small jars the yields were small, and when using big jars they took ages to colonize
- When I put them in my improvised fruiting chamber a lot of cakes got contaminated. (Again, this is no problem when you use proper sterile techniques and have a bad-ass fruiting chamber but in my experience this was quite hard)
So I had moderate succes, but by no means as good as with the grow kits. That's when a friend said to me: 'Why don't you make your own grow kits then?'. Awesome idea, as all the ingredients are available online for a few bucks. So here is my TEK:
Ingredients:
- Pressure cooker (large enough to hold your filter boxes)
- Filter boxes (I have 1200 ml rectangular ones. I recommend rectangular ones because they colonize faster.)
- Filter bags
- Organic brown rice flour
- Vermiculite
- Water
- Spore syringe (easy to make, not described here but just google it)
The ratio of dry vermiculite to BRF should be 3,5 to 1 (in volume).
Start by putting your vermiculite in a big bowl and add water until it's saturated. If you add too much let it drip out. Then add your BRF and mix it up.
Loosely fill up your filter boxes to 1 or 2 cm beneath the edge with the substrate you just made.
Poke 4 holes in the lids of the filter boxes, 1 in each corner. Then ducktape them shut. These holes are for inoculating.
Now it's time to sterilize your filter boxes in a pressure cooker. Put a few cm of water in your pressure cooker. Use a rack to keep the filter boxes from touching the bottom. When you put the filter boxes in, don't shut the lids completely! This will cause the boxes to expand and deform. Keep the lids 1/4 open, and cover the boxes with aluminum foil to keep the water from coming in.
Now pressure cook them. I like to be on the safe side and cook for about 2 hours.
Let them cool, then take them out and close the lids. Discard the aluminum foil. Now take your spore syringe, lift up the ducktape until the hole is exposed and squirt a bit of spore solution in the filter box (along the edge of the box so it spreads to the bottom). Put the ducktape back in place. Do this for every hole in every filter box.
Now the filter boxes are inoculated! All we have to do is play the waiting game. If you keep the boxes at high temperatures they will colonize faster, but they'll colonize fine at lower temperatures too. Just don't get them above 30 degrees Celsius. 26 is generally considered a good temperature for colonizing, 23 for fruiting.
In the beginning I used a double tub setup with an aquarium heater in a layer of water in the bottom tub to keep my temperatures high. This is a pretty good way to regulate temperature. 
However my heater fluctuated too much so I stopped using it. Now I colonize and fruit at room temp (19 C). It takes a little bit longer but that's not a problem for me. Colonizing at lower temperatures has the advantage that it doesn't have the risk of drying your cake out too much.
Once the boxes are completely colonized it is time to birth them. The fungus used up most of the available water during it's growth, so rehydrate the cake. This is done by opening the lid of the box and filling it completely with water. Close the lid and let the cake suck up water during 12-24 hours. After that pour the remaining water out and take the lid of. Now put the filter box in the filter bag, fold the edge of the bag and secure it with paperclips.
Before you put the box in the bag, it is very useful to ducktape the sides of the box so no light gets through. If you don't do this you will have shrooms growing from the side of the box that you will have to dig out.
So, now you have the colonized box in the bag. Just put the bag somewhere and shrooms will grow (I forgot the ducktape on the side in these pictures). 
After each harvest you have to rehydrate the cake. With the 1200 ml box I get about 4/5 harvests and a total of ~40/50 grams dry.
The filter boxes and bags are both reusable many times, just sterilize them in your pressure cooker.
I hope this is useful for some lazy growers, like me. This is really almost impossible to f*ck up, the bags are small and easy to conceal, supplies are legal in every country, and it's very cheap with fine yield.
