Casing and Fruiting

Nan's Nook : Archives : Misc Tek : 9er Tek

  Working with casing is the main art of mushroom cultivation.

  One good casing recipe is: equal parts of peat moss, vermiculite, and crushed oyster shell with enough water to moisten.  It seems that pasteurizing at  160 - 170 deg F for an hour or so is the best treatment for casing. This can be done in a big bowl in the pressure cooker.  Don't close the lid or put the jiggler on.  Just lay the lid in place and turn the heat on low (or very low) and measure the temp of the casing with an appropriate thermometer occasionally.  When the casing temp gets to 170 deg, turn off the heat and allow to cool slowly. Don't remove from the burner until cool.

  Take an empty distilled water jug (1 Gal.) and cut off the top to leave a container about 3 in. deep.  Pull out enough Al foil to go from one top edge around the bottom and up the other side.  Fold about 1/4 in. over the top edges of the container.  If you must use tape to hold the Al foil in place, don't use masking tape and keep the tape outside of the container.  Plastic based tape will not encourage mildew/mold/bacteria growth like the paper based masking tape.    The idea here is to block the sides from the light so all the fruit grows on the top.

  Put in enough casing to make a flat bottom, then you can put in 2 one pint cakes lying on their sides (or 3 or 4  1/2 pt. MMGG cakes.)

Spoon casing around the cakes.  Shake gently to settle the casing.  Pull out on the sides to work the casing in until the container is sort of rounded and the cakes are covered with about 1/2" of casing.

  Up to 3 of these containers can be placed in a standard 10 gal. aquarium, but 2 allows for easy maneuvering and picking.  Sometimes it's difficult to keep the humidity up with only 2 containers/aquarium, so go for whatever seems to work best for you.   The casing should be misted 2 or 3 times per day.  No further humidification is necessary (except in very dry climates.)  In fact, when the pinheads appear, it is best to open the top some.   About 1/4 in. wide and the length of the aquarium works well.

When the mycelium becomes visible at the top of the casing, it won't be long before pinning starts.   At this point, one should stop misting the casing directly.   Direct moisture will damage the pins.   The pinning means you've done your job well and the mycelium has decided there is ample moisture for fruiting.   If you do decide to mist the casing around the growing fruit, be careful.   Too much water can cause the flush to abhort.

Notice the condensation on the walls in the picture below.  That was with the lid open 1/4" and misting only for humidification.
It really helps to keep the temperature around 75 deg F in the fruiting chamber.  It's much easier to keep the humidity up.  The fruit will grow slower than at higher temperatures, but they'll be of higher quality.

  It is very easy to over humidify a cropping chamber if you use perlite with cased cakes.   The evaporation from the casing is important to the growth of the fruit.  If the walls of the aquarium are totally covered in condensation, the humidity is too high for cased cakes (it's great for uncased cakes) and you may see bacterial blotch on the fruit.  This causes slimy black lesions and pits on the fruit.  If the humidity is not corrected, the fruit will be wiped out.   Some of these bacteria are harmful to humans, so be careful to wash well after removing contaminated fruit.  Lowering the humidity will almost always clear up the problem and allow proper growth to resume.   The upper limit on humidity for cased substrate is 92% (per Stamets)   (The picture above reflects a slightly too high humidity.)