Casing of magic mushrooms cakes
Step 8. Day 15-18. How to make Mushroom Cakes and Casing
The colonization stage in incubator is completed. At this point you've already have spawn grain in order to move on casing.
This step is not necessary for getting psilocybe mushrooms, but it has several advantages. By mastering this skill, you will be able to increase your yield significantly and improve your skills in mushroom cultivation techniques.
Casing is not a complicated process at all. We wanted to describe it as briefly as possible, but then we went into explaining the basic principles of chemistry and mycology, which related to casing in simple terms. We think it will be useful to know for every cultivator.
Video «How to make Mushroom Cake and Casing»
Our casing process looked like this:
What is casing?
Casing — is a technique when spawn grain is broken into small pieces and covered with a moist, non-nutritive layer such as peat, coconut peat or coconut fiber, vermiculite and mix of all these ingredients.
Casing layer — is a secondary substrate; it is not supposed to provide nutrients for fungi development. Casing layer should have a low nutrient value compared to the main substrate. If the casing layer is nutritious, mushroom mycelium continue its vegetative growth until it had taken over the entire nutrient medium.
Casing stimulates mushrooms to develop fruit bodies.
This practice was developed by Agaricus mushroom cultivators. They discovered experimentally that mushroom pinhead formation is stimulated by covering the compost with such a layer. The cover layer promotes fruiting and increases the yield potential for many (but not for all) cultivated mushrooms.
Why do we need casing?
Mushrooms are 90% of water and the cover substrate not only provides hydration but also stores water until it becomes a source of moisture for the mushrooms themselves.
Casing layer has 5 main reasons:
- To protect the colonized substrate from drying out.
- To provide a moist microclimate for pins formation and further growth.
- To provide an additional water supply for fungi growing.
- Support the growth of microorganisms that improve fruiting.
- Additional contamination protection.
Main advantages of casing layer
Mushroom cakes/shoeboxes covered with casing layer may be considered preferable to open cakes (PF-tek) because:
- They produce more flushes, increase yield in terms of size and weight for each flush and in terms of overall harvested weight.
- They give a better understanding of the mushrooms life cycle for the cultivator. It's not just about psilocybin mushrooms. A basic knowledge of the life cycle can help newbie growers open the door to the world of gourmet mushrooms and medicinal mushrooms.
- Casing technique is often a milestone for more meaningful and complicated mushroom growing techniques.
Casing requirement by species
For most mushroom species it is optional step or not necessary at all. However, there are some mushroom species for which casing is a mandatory part of their life cycle. The table below shows some examples:
As you can see, casing is optional for Psilocybe Cubensis and Panaeolus subbalteatus strains. You can skip it and continue growing using the PF-tek. For PF-tek casing is not required for getting mushrooms.
If you decide to do without casing, then you just need to get the jars out of the incubator.
Open the jars. Remove the formed PF-cakes from them and put mushroom cake in growbox (fruiting chamber) for further development and fruiting.
Turn on the light (LED lamp or natural diffused light, not direct sunlight!). Low the temperature up to +21°..+23°C or 70-74°F (room temperature). This is necessary for the initiation pinhead/primordia formation. Ventilate 3-4 times/day.
In 5-10 days in the jars should form small white balls of mycelium, it's pinheads. In the next few days you can see very small mushrooms with brown caps - this is the start of fruiting.
So you can skip all steps below in this section and move on STEP 9. DIY Growbox. Fruiting conditions
Why newbie growers give up casing
Beginners are afraid of casing process for several reasons.
- Newbies think casing is a difficult technique. In fact, casing is much easier than all previous steps of growing.
- Casing involves extra steps are not necessary to get the fruit bodies. But yield without casing will be lower.
- Casing layer gives opportunities for contaminants (at several points in the process) compared to PF-tek. Sterility is also important for the casing process, but not as strict as in the previous steps.
- Casing involves "putting all the eggs in one basket" because the covered mushroom cakes/shoeboxes contain the amount of substrate equivalent to 2-6 PF-cakes. If one container contaminated, all the amount of mushrooms that could have been given from each mushroom cake separately will be lost.
- Mushroom cakes with casing layer require more attention to relative humidity in the growbox than PF-cakes.
- Casing process requires extra time for casing substrate preparation and additional attention to adjusting its acidity.
pH level adjusting. Why is it important for mushrooms growing?
In a casing substrate with a high acidity:
- nutrients are poorly assimilated
- mushroom growth is inhibited
- increases the activity of competitive microorganisms. It leads to decomposition of organic matter and substrate contamination.
In addition, the substrate is gradually acidified by mushroom waste products, which makes it even more vulnerable for molds. For example, if we applied a casing layer with a pH of 7.5, it gradually drops to a pH of 6.0 with each flush of fruiting. That's why contamination often appear on the 2nd, 3rd or even 4th flush of fruiting when mushroom cake is depleted and acidified.
What should be the pH level for the casing layer?
The acidity level of the casing substrate for different types of fungi ranges from 6.5 to 8.0.
The optimum pH for Psilocybe Cubensis is 6.8-7.2 - neutral or slightly alkaline soil.
Buffering agents for casing substrate
To balance and adjust the acidity of the casing layer we need to use buffering agents on the base of calcium carbonate (CaCO3). To do this, you can use:
✅ Limestone flour is the best and proven option for substrate acidity adjustment. It consists of 95-100% calcium carbonate (CaCO3). It uses in its pure form, additional preparation is not required. It is enough just to mix it with the substrate and water in the right proportions.
Limestone saturates the substrate with oxygen, promotes mushroom metabolism and reproduction of beneficial microorganisms, reduces the growth of pathogenic microorganisms and thereby increases the yield of mushrooms and the duration of the fruiting period (the number of fruiting flushes).
Limestone grit are also used. The difference between flour and grit is only in the size of fraction.
✅ Dolomitic limestone flour (CaCO3-MgCO3) - consists of 50-75% calcium carbonate and contains about 25-50% magnesium carbonate (MgCO3). Some researchers have reported depressed mycelial growth in casings high in magnesium.
✅ Marl. Dredged from dry lake bottoms, marl is a soft lime similar to chalk but has the consistency of clay. It is a composite of clay and calcium carbonate (50-75% and 25-50% insoluble residue (SiO2 + R2O3)) with good water holding capacity.
✅ Chalk (CaCO3) is a kind of limestone, consisting of 75-95% calcium carbonate and about 5-25% magnesium carbonate (MgCO3). But it is not the kind of chalk used for boards.
✅ Oyster Shell. Comprised of calcium carbonate, ground up oyster shell is similar to limestone grit in its buffering action and ifs structural contribution to the casing layer. But oyster shell should not be used as the sole buffering agent because of ifs low solubility in water.
✅ You can also use liquid pH+ buffer agent for hydroponics, substrates and soil. The concentration is adjusted with a water solution based on the volume of the substrate according to the instructions on the package.
🔴 Gypsum is not a buffering agent itself. It has a neutral pH. The base of gypsum is not calcium carbonate (CaSO3), but calcium sulfate (CaSO4). It can be added as an additional ingredient to the basic buffering agent and change pH level up to 7.0.
Base for the casing layer substrate or spawn to bulk substrate
The base for Casing layer substrate and Spawn to Bulk substrates are:
- peat soil
- coconut peat soil
- pressed coconut fiber in bricks
Depending on the type of peat differs its acidity.
- Upper (sphagnum peat) acidic - pH 2.5-3.5. Able to hold up to 2 times more moisture than coco peat.
- Transitional or prepared acidified peat has a pH of 5.0-6.5.
- Lowland peat has a neutral pH of 6.5-7.0 due to its high calcium content.
Coconut fiber is an excellent moisture retainer and when soaked increases in volume by 10 times. On the packages with ready-made peat, coconut soil, coconut-peat soil and coconut bricks manufacturers always indicate the acidity. Usually the pH is 5.5-6.5.
How to determine soil pH level
The easiest way is to use litmus paper (cost about $1 for a pack of 50-100). Take distilled water and mix it with the soil in a 1:1 ratio. Use litmus paper to determine the pH level of the soil based on the color.
Another option is to buy an electronic soil tester. You just insert the tip of the tester into the soil and after a few minutes you can see the result. The price of such device starts from $5.
If you don't want to bother with it, you can use acetic acid in the case. It is necessary to take a sample of soil and water the moistened composition with a small amount of vinegar. If no bubbles appears, then the soil is alkaline, if the amount of bubbles is small, then neutral, with a large amount of foam the soil has an acidic medium. Of course, this method will be very approximate and you will not be able to adjust the pH level exactly in this way.
List of required stuff for casing
1️⃣ Grower outfit: medical gloves, mask, cap, raincoat or gown.
2️⃣ Spawn jars or spawn bags.
3️⃣ Coconut peat soil or coconut fiber brick.
4️⃣ Calcium carbonate (CaCO3) for pH adjusting: limestone flour, limestone grit, chalk, marl, limestone dolomite flour, oyster shell.
6️⃣ Jars and lids for sterilization of casing substrate. The jars are exactly the same as for grain sterilization. Heat resistant spawn bags also suitable.
Make a hole in the lid (for steam circulation during sterilization) and cover it with a breathing patch.
7️⃣ Flat plastic containers (volume about 1-1.5 liters) for mushroom cakes or mushroom shoeboxes.
8️⃣ Alcohol (70%) in a spray bottle.
9️⃣ Tablespoons - 2 pcs.
🔟 Boiled chilled water (about 1 liter).
1️⃣1️⃣ Cotton disks.
1️⃣3️⃣ Pressure cooker/ autoclave/ multicooker/ oven or microwave.
Here is the list of formulas for the casing substrate. They can be used not only for Psilocybe Cubensis and Panaeolus, but also for other species for which casing is a required process of cultivation.
❇️ Formula №1 (the simplest and most common)
- Coconut-peat soil or coconut fiber - 2 parts
- Vermiculite - 2 parts
- Limestone flour or limestone grit - 1/2 to 1 part
- Water - about 1-1,5 parts
❇️ Formula №2 (variation of the first formula)
- Coco peat or coconut fibre - 4 parts
- Vermiculite - 2 parts
- Limestone powder or limestone grit - 1 part
- Water - about 1,5-2 parts
❇️ Formula №3 (according to Paul Stamets)
- Coarse peat (sphagnum) - 4 parts
- Limestone flour - 1 part
- Limestone grit - 1/2 part
- Vermiculite - 1/2 to 1 part
- Water - about 2-2¼ parts
❇️ Formula №4 (according to Paul Stamets)
- Coarse peat (sphagnum) - 2 parts
- Chalk or marl - 1 part
- Vermiculite - 1/2 to 1 part
- Water - about 1-1¼ parts
The "Vermiculite Casing Layer" Experiment! Often growers practice only sterile moist vermiculite as a cover layer, instead of peat/coconut based substrate. We don't recommend such casing layer. For us, it only causes additional problems with the moisture balance during the fruiting period and provokes contamination. The results of the experiment are in the section Growing Experiments.
How to prepare substrate for casing
1️⃣ Mix all the ingredients according to the chosen formula. We often practice formula #2.
We use ready-made coconut-peat substrate or bricks of coconut fiber.
If you use dry coconut fiber in bricks soak it in water. It increases in volume by 10 times. Then squeeze the coconut fiber a little, mix it with vermiculite and add limestone flour. Thoroughly stir the mass. You will get a kind of messy mush, which we put in jars and sterilize in the same way as we did for the grain substrate.
2️⃣ Fill the jars with the prepared substrate.
3️⃣ Fill another jar with dry vermiculite and add 100 ml of water to it. Stir.
4️⃣ Close the jars with a lid with a hole and a breathable air filter. Wrap the lid with foil. Jars and lids are the same as for sterilizing grain. Heat-resistant bags also suitable.
5️⃣ Place all jars to the pressure cooker/multi cooker at +120°C (~250°F) for 1 hour for sterilization. The process is the same as the substrate sterilization step.
You can do the sterilization in the oven at 180°C (~350°F) for 1 hour. Or place the casing substrate in heat-resistant bag and heat in the microwave at maximum power for 5 minutes, then shake/flip the substrate and heat for another 5 minutes. But we always trust this process to the pressure cooker or multicooker.
6️⃣ Let the substrate and vermiculite cool to room temperature.
Preparation for Casing process
1️⃣ Wipe the table, plastic boxes, tablespoons, jars with casing substrate and vermiculite with alcohol.
2️⃣ Take the spawn jars or spawn bags out of the incubator.
3️⃣ Without opening the jars check each one for the presence of contaminants.
Make sure there are no contamination in them. If you notice blue-green, green, olive, gray, red, pink, purple or black spots, the whole jar should be tossed without opening!
Even if there is healthy white mycelium of Psilocybe Cubensis in that jar with the contamination, don't spare and throw the entire jar away, because it is already contaminated. Contamination can affect neighboring healthy mushroom cakes in the future. Taking away the healthy mycelium and throwing away contaminated parts won't work! Mold spores spread easily and imperceptibly over the substrate.
If you see any signs of mold, bacterial contamination or doubtful areas - throw such jar away!
Casing process step by step
1️⃣ Put some sterile vermiculite in plastic container just to cover the bottom (about 0,5 cm).
2️⃣ Open the spawn jar or spawn bag.
3️⃣ Check each jar for contamination and pick only the good ones.
4️⃣ Move the spawn grain into a flat plastic container. You can do it with sterile spoon. Don't afraid to crush the substrate. It's okay to put 2-3 jars of the same strain in one container. Don't mix different strains!
5️⃣ Remove substrate parts are not covered with mushroom mycelium. Uncovered substrate can't be used! Without mycelium it will become sour and mold will settle on it.
The small mushrooms that have already formed should also be removed. If we leave them, they can start to decay and provoke contamination.
6️⃣ Spread the spawn evenly. But don't press it down! Fill the container with substrate and leave 3-4 cm to the top of the container, because we need 1-1.5 cm for casing layer.
7️⃣ Put the layer of sterile casing soil on the top. About 1-1.5 cm, no more! The soil should be wet. Pressing it down should release water. If there is too much of water and it flows from the soil, you need to squeeze the soil. If there is not enough liquid, add cooled boiled water.
Note! It is convenient to add water simply by dripping from the syringe on the soil in the palm of the hand or to drip from the syringe casing layer on the cake. In our case, we squeezed a little.
8️⃣ Wrap the containers with foil (all sides). This is to give the mushrooms an upward direction of growth, not on their sides. Non-transparent containers also suitable, the only disadvantage you won't be able to see possible contamination that might show up inside.
9️⃣ Spray the mushroom cake several times with boiled chilled water from a spray bottle.
🔟 Cover gently each cake with foil to keep out the light. You can cover them with a plastic lid from a container. But don't close tightly, you need to leave air access. Foil or plastic lid should NOT touch the casing substrate!
1️⃣1️⃣ On the top of foil (or on the lid) make a few small holes with a needle for air access.
1️⃣2️⃣ Put mushroom cakes after casing back to the incubator for casing colonization. Approximately 3-5-7 days.
Maintain incubator conditions the same as for substrate colonization: temperature +27°..+29°C, no light at all, humidity 30-55%
How to identify when we need to move cakes to the grow box?
At this stage, the colonization process is more dynamic and you can observe changes every day. Check cakes every day and assess casing colonization level.
✳️ Two days after casing:
✳️ 4 days after casing:
Moving cakes to the growbox
If 50-60% of the coconut soil is colonized by psilocybe mycelium it's time to prepare the growbox or fruiting chamber and start fruiting period.
On the photo below are mushroom cakes 4 days after casing. They are ready to move into the growbox. We could put them in growbox even a day earlier.
🔴 Don't keep cakes in the incubator too long! It's dry in the incubator and the lack of moisture can cause the cakes to get a thick coat of mycelium (overlay). Then fruit bodies can't grow. You need scrape off mycelium layer with a fork and then hope for mushrooms.
We faced with this problem during our growing. As a result, we totally lost harvest of strain F+. Here is a detailed section of What is overlay, abortions, metabolites and waste products of psilocybe mushrooms?
After successful casing colonization it's time to move on —
Feel free to ask any questions and leave your comments ⬇️⬇️⬇️