German TV can be a cornucopia of documentaries. Of course: Hitler. Up and down. I can’t stand that guy anymore, just because of his omnipresence. This is presumably the most reliable way to prevent something like this from ever happening again – grinding people’s last nerves with it 🙂

But also interesting stuff! Like for example on professional mushroom growing in an old airforce aircraft shelter. Made me try some cultivation bags on my own again, as I found a left over box of store-bought mycelium in the shed. I didn’t have a clue if it was still any good, but it was worth the try and as usual, I had a little fun.

What you need:

(for two growing bags)

– Mushroom spawn (any variety that’ll grow on straw, e.g. king oyster, blue oyster, bay bolete, etc.)
~ 2 l straw pellets (from the pet shop)
– 4 generous tbsp. of wheat bran (~ 5-10% dry weight)
– Some gypsum (~ 2% dry weight)
– 2 ziploc freezer bags, 6l (a brand that can resist boiling water)
– Some Micropore™ tape
– Cooking spoon
– Disinfectant spray
– Latex gloves

What to do:

Step 1: Bring water to a boil and disinfect everything. Spray the inside of the freezer bags, close them and set aside for 5 minutes. Sterilize your spoon, wear gloves and rub your hands with disinfectant.

Step 2: With gloved hands, use some kitchen towel to wipe out the inside of the bags. Eyeball ~ 1 l straw pellets into each bag and add two generous spoons full of wheat bran and the gypsum. Stir with your spoon until well mixed, close the bag.

Step 3: Put the bags in a pot each (so they can stand upright without toppling over). Open the bag, pour in ~ 1 l boiling water, stir, and close the bag, leaving a small opening for the steam to escape. Let the pellets soak for some minutes. The goal is a very moist, but not soaking wet straw-bran-mixture, so you might have to add more boiling water after a couple of minutes. You should have two two-thirds-filled bags now. Close the bags completely and let cool down to room temperature.

Step 4: With gloved and disinfected hands, carefully open your mushroom spawn. Divide it into the two bags and mix it in with your (you guessed it! disinfected!) spoon. Close the bags again, stand them upright and shake them so the contents gather in the lower half and you have an empty upper area.

Step 5: Disinfect a pair of scissors and, in about the middle of the upper half of the bags, cut an opening, a little smaller than the size of your micropore tape. Tape it close immediately with a double layer. I like to give the taped area a small spray of disinfectant. You can note the date and type of mushroom on a sticker.


Store the bags in a dark, warm and humid spot and wait for the mycelium to colonioze all of the substrate. This may take several weeks. Occasionally check for growth but also for mold and throw away, crying, if necessary. If you worked cleanly and hygienically, chances are good the mushrooms establish dominance and no bad funghi can proliferate.

When grown through, you can begin to try and make the mycelium fruit: Make two crosswise incisions, lower the temperature a little and give it a little more light. Make sure it gets enough oxygen and watch the shrooms sprout.

Edit: I’m already harvesting the second wave of oysters! *proud*