Agar media

Agar media is made from seaweed and is used to solidify media. The agar used in mushrooms cultivation is usually available in powder form. By adding a nutrient such as malt extract it can be used to germinate spores and grow mycelium.


An autoclave is a piece of equipment used to heat up substances above the boiling point. This is why the autoclave is ideal to sterilize your instruments and nutrient soils.

The autoclave is no more than an expensive and luxurious pressure cooker. For the home grower a pressure cooker is more than enough. If you intend to grow large quantities, however, you should consider a autoclave.


Bacteria are the most common cause of contamination for mushroom cultures. These one-celled microorganisms are a continuous danger for the mushroom. They compete with the mycelium for the nutrient soil. Surely in its early stage the mycelium is very weak and often not resistant to aggressive bacteria. This is why sterilizing is so important, so that all the bacteria are killed.

If the substrate is totally colonized, it’s a little less vulnerable to the bacteria. The mycelium is then strong enough to mosly dominate the bacteria. This is however no reason to be less careful with the hygienic rules.

Bacteria in the substrate may apear in all sorts of colors. The most common colors are yellow, orange, black and green.

Casing layer

The casing layer is a cover of humid material to apply over the colonized substrate. Although most mushrooms will also grow without a casing layer, it’s wise to use one.

The casing layer keeps the substrate from drying, stimulates the forming of primordia and works as a water reservoir for the adult mushrooms.


The mushroom mycelium builds up carbon dioxide. This carbon dioxide will spread over the whole growing area. As this area is normally quite small, it gets filled with carbon dioxide very fast. Mushrooms find it very difficult to handle high concentrations of carbon dioxide. The growing of the mushrooms will also rapidly come to a stop.

To prevent this from happening it’s important to refresh the air in the growing area regurlarly. When the substrate has been exposed to the fruiting conditions and the first pinheads come out, it’s very important to refresh the air very often. 

The amount of fresh air for an optimum growing environment varies per type of mushroom. At the same time this depends on differents factors, like for instance the size of the growing area.. In general the mushrooms from the Panaeolus family have a bigger need for fresh air then the mushrooms from the Psilocybe family.

Psilocybe: refresh the air 3 to 4 times per day (minimum)

Panaeolus: refresh the air 6 to 8 times per day (minimum)

Cold Shock

A cold shock means that you store the colonized substrate with a casing layer and a closed top for 24 hours at 2 to 4º C, before you introduce it to the fruiting conditions. This works as some kind of trigger, so that the mycelium understands that it’s time to grow into a beautiful mushroom. For some types of mycelium the cold shock will increase yields.


A spore which comes in contact with the right nutrient soil under the right circumstances will germinate. This will start with the forming of the primary mycelium. This mycelium is often called ‘monokaryotic’ mycelium.

When this mycelium comes in contact with another compatible monokaryotic mycelium, secondary mycelium will start forming. This secondary mycelium is called ‘dikaryotic’ mycelium.

Dikaryotic mycelium is therefore the result of the joining and melting of two sorts of monokaryotic mycelia, which then proceed as one. Only the dikaryotic mycelium will germinate mushrooms. The monokaryotic mycelium on its own cannot grow into a mushroom. The chance that only monokaryotic mycelium will grow in your substrate is generally very small.


Due to the necessary sterilization, your hands, arms and the working space must always be properly disinfected. Disinfecting means killing all the bacteria or preventing them to appear. Good disinfecting products are alcohol and Dettol mixed with water.

Disinfecting is extremely important, but you must be careful: too much can be dangerous! A big amount of disinfecting substances in the air can damage your health. So pay attention to the quantities. After cleaning leave the room for about 15 minutes, so that the disinfecting product can do its job. Besides, disinfecting products are extremely flammable! Be very careful when you use fire in a disinfected space to sterilize certain instruments.

Filter bag

Filter bags are specially crafted for the cultivation of mushrooms. These bags are autoclavable and have a special filter. This filter lets the air through, but keeps (most) bacteria out.

The filter bags are very easy to handle and can be used for multiple purposes.

  • to grow mycelium
  • as a mini growing area


Mushrooms appear in so called flushes. A flush means a collective rise and growth of a group of mushrooms within a (normally) small period.

A substrate with a strong mycelium can produce several flushes. The speed of growth and size of the flushes varies per type of mushroom. Some types of mushroom can give 5 to 6 flushes per substrate.

Fruiting conditions

Fruiting conditions means that you will place the open substrate with the casing layer somewhere where there’s light, fresh air and lower temperatures.

When the substrate is totally colonized by the mycelium, you will add the casing layer. Then, put it back in the incubation room for a few days. When the mycelium comes through the casing layer, it’s time to leave it open to the fruiting conditions. Thanks to placing the substrate in the fruiting conditions you give it the chance to form fruit bodies.

Glove box

A glove box is a semi-sterilized air closed small space where you can only work with your hands. You can stick your hands in through 2 holes. Because the space is small and air closed, there’s little or no bacterial movement in the air, thus the possibility of infection is minimal.

It’s not difficult and it certainly doesn’t need to be expensive to make a glove box. The glove box is actually the best option for those who have a low budget but want to take their mushroom growing to the next level.

HEPA filter

HEPA stands for High Efficiency Particulate Accumulation. These filters clean 99, 97 % of all particles of air bigger than 3 micron. Mushroom cultivators use these filters to make a laminar flow hood. By blowing air from a ventilator through these filters it’s possible to create a filter that produces air as good as sterilized. The possibility of infection becomes close to none. A laminar flow hood with a HEPA-filter is an interesting device for the experienced grower who wants to develop his mushroom cultivation. A laminar flow hood is a reasonably expensive investment, but when the mushroom growing hobby becomes out of hand, it’s surely worth it.


Humidity is the percentage of water available in the air. A high humidity level is extremely important during the growth of the mycelium and the fruiting period. Most types of mushrooms incubate best with a humidity level of more than 90 %. During the fruiting conditions it’s wise to let the level of humidity in the air go down to 85-90 %.

You can keep up the level of humidity in the air if during the formation of primordia you spray it daily with water. During this period it’s very important to moisten the air with a mist of water. Do not spray the water directly on the casing layer. Big drops of water are dangerous to the mycelium.

A better method to control the humidity in the air is to use perlite. Perlite is a great keeper of mist. Applying a layer of perlite on the terrarium with some water will keep the humidity on a constant reasonably high level.


The incubation period comes after the inoculation. During this period you give the spores the time to germinate and the substrate will grow with the mycelium.

Mycelium grows best under warm circumstances. Place the substrate therefore in a warm space. The mycelium of most mushrooms grows best at a temperature of about 28 – 30 degrees C.

On small scale cultivation a closet over the refrigerator is a good place. The refrigerator is warm on the backside and this warmth increases. On a larger scale you must get a thermostat or another warming system.

However keep in mind that the substrate with mycelium also produces its own warmth. Besides the warmth the incubation space must be completely in the dark. A dark place fastens the growing pace. Light can also cause premature growth of the mushrooms.


Inoculation means applying spores or spawn in what will be used as substrate or nutrient media.

During inoculation it’s extremely important to work in a sterilized environment. During this stage the spores and the substrate are very vulnerable to contamination.

You can inoculate the substrate with:

  • Spore prints
  • Spore syringes
  • Mycelium on agar
  • Live tissue
  • Spawn

Laminar flow hood

A laminar flow hood is a small space where with the help of a ventilator and an HEPA filter an almost perfectly sterilized environment can be created. In a good laminar flow hood you can do your cultivation work with barely any risks.

HEPA stands for High Efficiency Particulate Accumulation. These filters clean the air from 99, 97 % of all available particles bigger than 3 micron. If you let air from a ventilator blow through the HEPA, you create a flow of air on the other side of the filter. This air is free of eventual contamination. It also keeps away the air coming from your direction. And this is precisely the air flow which is filled with airborne contamination. Thanks to this filter you can work in an environment as sterile as possible. It’s very important that the ventilator has exactly the amount of power needed for the size of HEPA filter that you’re using. If the ventilator isn’t powerful enough the air flow coming through the filter will be too little to guarantee a sterile space to work in.

A laminar flow hood with a HEPA-filter is an interesting device for the experienced grower who wants to develop his mushroom cultivation. A laminar flow hood is a reasonably expensive investment, but when the mushroom growing hobby becomes out of hand, it’s surely worth it.


A spore from a mushroom which germinates starts with the formation of primary mycelium. This mycelium is also called “monokaryotic” mycelium. Monokaryotic mycelium on its own cannot form mushrooms.

The monokaryotic mycelium must be placed in contact with another compatible monokaryotic mycelium. Secondary mycelium will then start to form. The secondary mycelium is called “dikaryotic” mycelium. Only dikaryotic mycelium can form mushrooms. The chance that only monokaryotic mycelium will grow in your substrate is generally too low.

Multi spore

A multi strain culture is a mushroom culture that contains an array of spores that could each develop into different, unique mushrooms with their own traits.

Whenever a print or spore syringe is used to inocculate the substrate, it is called a multi strain culture. The ‘different’ spores will germinate inside the substrate, and form mycelium. A multispore culture can be the reason that many mushrooms in the same flush have different looks and develop at a different growth rate.


The mycelium is actually what the growing of mushrooms is all about. Mycelium is an underground network of cells which can spread over a big surface. The fruit of the mycelium is the mushroom.

In nature the mycelium can form quite large networks. These networks do not mean that the surface with mycelium will automatically be full of mushrooms. The mushrooms grow only where the ideal growing circumstances are gathered.

The mycelium from mushrooms containing psilocybin is white. Strong mycelium also has a somewhat stringy structure (rhizomorph).


Overlay is a situation that is best avoided. Under circumstances that are not ideal, mycelium is able to overtake the casing layer. This overly colonized casing layer is called overlay.

In this case it is difficult for the mycelium to pin, rendering the casing layer useless. 

Overlay can be prevented by introducing the mycelium with the added casing layer to fruiting conditions at the right time. After adding the casing layer the substrate needs to be put back in the incubation room for some days. When the mycelium is visible on 20 to 30 percent of the surface, introduce the mycelium to fruiting conditions. Cold shock can have a positive influence in preventing overlay.


Pasteurization in mushroom cultivation is the process of heating the substrate for a short period, thereby killing viable pathogens so they are unlikely to cause contamination.


Perlite is made of small pieces of extremely porous volcanic rock. It is used to keep the humidity high. Cover the bottom of the grow chamber with perlite, and spray it with some water to maintain humidity.

Petri dishes

Petri dishes are used to cultivate myclium on agar. They ususally come pre-sterilized, and ready for use. When working with a large number of petri dishes, consider using a petri dish holder. A holder allows you to stack the dishes on top of eachother.


When mushrooms start to emerge from the casing layer, we call them pinheads. Pinheads grow into mature mushrooms.

Pressure Cooker

A pressure cooker is a necessity for every mushroom cultivator. A pressure cooker is used to sterilize substrate and instruments by exposing it to high temperatures under high pressure. Sterilisation destroys all micro organisms.

Although pressure cookers don’t come cheap, it remains of the few somewhat more expensive items a mushroom cultivator needs. All other needed materials are relatively inexpensive.

After sterilisation the cooker needs time to cool down. Remain patient, don’t try to open the lid too fast. Too much pressure can render the substrate and jars to become useless. It can also lead to dangerous situations.

Primordia formation

Primordia formation is the stage after the emerging of pinheads. When the pinheads have grown in size, the stem will become visible. This stage is called primordia formation, and along with the pinhead forming this is a crucial moment in cultivation. Circumstances need to be perfect in order to achieve good results.


Psilocin is one of the two active compounds that appear in magic mushrooms. The other active compound is psilocybin. These alkaloids are closely related to each other and are regarded as psychedelics.


When cultivating mycelium in petri dishes, there are two distinguishable forms of mycelium. One type grows somewhat fluffy, while the other type has the structure of plant roots. When working with cultures, the latter is the one to be selected for further cultivation. Rhizomorph mycelium is likely to grow into healthy, large flushes.


Sclerotium (plural sclerotia) is a solid mass that can appear in the substrate. Species known for producing large amounts of sclerotia are Psilocybe Tampanensis and Psilocybe Mexicana.

Sclerotia somewhat looks like walnut and can grow the size of a tennis ball. There are various methods of cultivating sclerotia. When the cultivator chooses to grow mushrooms of said species, sclerotia will form underneath the casing layer. Another option is to grow only the sclerotium. With this method, the substrate is not introduced to fruiting conditions, and no mushroom forming will take place.

Sclerotia of these strains contain both psilocybin and psilocin.

Single strain

A single strain (or pure strain) is an isolated unique genotype. A substrate inoculated with a single strain has a bigger capacity to produce beautiful, strong flushes.

The experienced grower will therefore look for these single strains. Single strains can be produced by growing mycelium on agar and by isolating the rhizomorph pieces of mycelium.

Using the live tissue technique also creates a single strain.


If you wish to keep certain cultures of mushrooms for a prolonged time, it is recommend to do so by using the so called slants. These are test tubes filled with agar for mycelium to grow.

The slants can be sterilized with the agar extract inside. If you let the slants cool down after sterilization it’s wise to set them down. This gives the mycelium a bigger surface to grow in. After it’s cooled down you can inoculate the slant with for instance an isolated piece of mycelium from a single strain. When the mycelium gives signs of growth on the agar you can place the slants in the refrigerator (2 – 4 degrees C.).


Spawn works as inoculant for the substrate. It’s actually a small bit of mycelium (preferably from a pure strain) which you spread over the substrate. Here the mycelium has the chance to develop itself. Spawn must be divided evenly over the whole substrate to obtain a proportional growth.

Rye is the most common spawn used. A pot of rye which is totally colonized with mycelium can be an excellent spawn for another 10 pots with rye or a filter bag with pasteurized straw.

If you use spawn make sure that it is totally free of contamination.

Spore print

A spore print is a piece of paper (tinfoil or glass slide) used to collect the spores of a particular strain.

To start growing mushrooms one must first get a spore print. A spore print can be obtained from a mushroom found in nature.

Spore prints are also widely available on the internet. Several websites dedicated to the cultivation of mushrooms offer spore prints for sale. There are also numerous forums where cultivators exchange spore prints. In most countries it is not illegal to possess a spore print.

Spore syringe

A spore syringe is a syringe with spores of a mushroom in sterilized water.

The inoculation of the substrate is generally done with the help of a spore syringe. Theoretically it is possible to inoculate the substrate directly with the spores of a print, but in general these are too dry to be able to germinate. To get around this you can let the spores dehydrate in sterilized water and absorb them with a spore syringe. The spore water in the syringe can then be used to inoculate the substrate.

1 cc of a spore syringe should be enough to grow mycelium. A bigger amount can speed up the growth, though.

A flawless sterilization technique is essential for making spore syringes.


The substrate is the nutrient soil where your mushroom can grow. So you can call substrate to all types of nutrient soils. There are many types of mushrooms, and all of them have their preferences for a certain type of substrate.

For example rye, flour, vermiculite, straw, manure, bird seeds, paperboard, wood chips can be used as substrate.

Tissue culture

A tissue culture is a culture based on a piece of tissue from (the inside of) a mushroom. With a tissue culture you can clone a mushroom.

If you grow mycelium with the help of a mushroom tissue, you can be sure you will get flushes with the same genetic characteristics of the mushroom from which you extracted the tissue. This process is best carried out by using agar. Make sure you extract tissue from the strongest and healthiest mushroom.