Mycelium for professionals

Frequently Asked Questions - Production


“Spawn” or “mushroom spawn” (sometimes wrongly called “mushroom seed”) is any material that has been inoculated with mycelium and used as a carrier to transfer the mycelium to a growing substrate.

With spawn, growers are assured of a pure, disease free culture that can be easily distributed throughout a growing substrate. Spawn comes in many shapes and forms: solid on grains, solid on sawdust, liquid on extract medium, liquefied on powder medium, etc. Mycelia sells spawn of a large number of species, on many recipes and of more than 150 strains to over 100 countries. Needless to say this variation is our specialty and our main sales product.


Mother spawn is the name we give our 2nd and 3rd generation of inoculum = before the 4th generation spawn. It can be produced on many types of carriers: grains, sawdust, slurry, liquid or any carrier which can grow fungi.


  • “Mother spawn” is not an internationally accepted term for this stage of multiplication, the term was invented at Mycelia 40 years ago. But there is no internationally accepted name. Different institutions and companies give it different names: inoculum, inoc, spawn master, master, pre-spawn, etc. We are eagerly awaiting the day that the industrial and scientific community will agree on a common name for this production step.
  • There are not always 3 generations of multiplication before “spawn” is made. In the case of liquid fermentations for example, 2 generations are sufficient.


A petridish is a shallow transparent lidded dish that is mainly used in laboratories to grow bacteria, fungi and other micro-organisms on a culture medium. When the culture media on the bottom is based on a solidified agar solution, it is called an agar petridish or agar plate. 

There are hundreds of recipes, depending on the micro-organism(s) you want to study.

Two interesting all-round media for fungal growth are MEA (Malt Extract Agar) and PDA (Potato Dextrose Agar).

At Mycelia, all our cultures are grown on an MEA medium, with the exception of some species that have very specific requirements.

For the production of agar petridishes for quality control it is advisable to add extra glucose (20% of the total dry matter) to the MEA medium, in order to stimulate bacterial development and hence make infections visible. When sugar is added, the code changes to MEA+. In spawn laboratories, MEA+ agar plates are mainly used in quality controls to assess the growth of mycelium or reveal the presence of contaminations (moulds and bacteria). They can be bought on our Mycelia website in addition to mycelium products, on the cart page as you make an order.


Mother cultures and mother spawn are more expensive because they are evaluated through an extensive quality assurance system (microbiological and/or mushroom growing tests) before being released and introduced into a spawn production process.

These quality assurance tests are the guarantee that the quality of the mother spawn (axenic and vigourus mycelium) and the spawn performance is according to industrial standards.


Both are excellent.

But if you have a well organized lab with correctly functioning laminar airflow, agar petridishes plates have the advantage of a larger agar surface. Simply put, they are more practical.

But keep in mind that test tubes are better and safer than petridishes for long term storage: the stopper prevents the medium of drying out.


This question cannot be answered because it depends on many different factors:

  • Mushroom species
  • Growing conditions
  • Substrate used
  • Market requirements
  • And many more…


If you want to produce spawn, you will need a spawn lab, or at least a small version of a spawn lab.

You will have to deal with either mother cultures and mother spawn, which you can order from a company like Mycelia.

The production of spawn must be carried out in the most hygienic conditions, with the appropriate installations and by appropriately trained personnel.

Spawn production is a technologically very advanced type of indoor agriculture, which is why it is usually referred to as biotechnology.

Spawn production is not like growing substrates or mushrooms.

In short: if you wish to produce spawn on a regular basis and for professional purposes, you will need the essential expertise. We teach this expertise in our group trainings and individual trainings in cleanroom technology and we can also assist in the design and organisation of professional spawn laboratories.

We can teach you the basics, but we cannot take you all the way. It takes many years to reach a high level in spawn production. For more details on our group training on spawn production, click here.


Yes, you can easily order them by going to our website and selecting your strain(s) in our webshop.

Then select the option “Mother spawn – liquid” in the dropdown menu.

Our standard liquid products are sold in syringes and are ready-to-use. We produce 2 sizes: 15 ml and 500 ml. Click this link to check out the manual.

We can also produce larger batches of 250 litres in our mobile fermentors. Contact our R&D team if you would like a quote.

Yes it can.

But not always. There are certain combinations of species and recipe which can be transported easily such as Agaricus bisporus (White Button) on grains, or Lentinula edodes (Shiitake) on sawdust, etc.

And of course you must have taken sufficient precautionary measures regarding cooling and hygiene.

But spawn is a living product and must be transported cool and quickly. The transport costs are elevated and the danger of reduced quality – due to overheating and others – at arrival is not imaginary.

More in-depth information can be found in some transport questions in our FAQ “About my order”.


Spawn is a living product! Its shelf life depends on:

  • the strain
  • the storage temperature
  • the way it is stored.

Strains with slow-growing mycelium have the longest shelf life

In chronological order of appearance, the signs of the ageing process of spawn are:

  1. The mycelium / spawn becomes more compact
  2. Observation / formation of skins, crusts and lumps
  3. Production of colored liquid with or without unpleasant odor
  4. Autolysis (self-destruction) of the mycelium and disintegration / degradation / damaging of the spawn

In the signs of the ageing process (1) and (2) the mycelium is perfectly useable, although it is less crumbly than totally fresh spawn. Since the autolysis of the cells begins at the end of stage (3), it is recommended to use the mycelium before that time. In stage (4) the mycelium is dying and should be discarded.

We do not indicate the shelf life on our spawn bags. Some producers do, but we consider it too difficult to give a guarantee.


The litre is the unit of measurement used in the spawn industry to make different types of spawn comparable. 

Mushroom spawn is a generic term for any material that has been inoculated with mycelium and which is used for further multiplication. The litre is a unit of measurement that represents a portion of space, not a weightDepending on the nature of the materials you want to compare, they will be more or less heavy for the same volume.

These differences highlight the density of the materials, i.e. the mass that they occupy for a unit of volume. The density of these materials fluctuates:

  1. due to the nature of the material itself (rye, millet, sawdust, liquid, etc… )
  2. due to the humidity of the material obtained during the spawn production process.


We strongly advise against it. 

Agreed, it would save you a small amount of money. But our recommendation would be to use mother spawn to produce your spawn.

Why? In spawn production, it is essential to avoid too many multiplication steps (mycelium transfers) in order to avoid risk of contaminations and strain degeneration. Mother spawn follows strict rules of quality control before being released. It is the safer way to start a spawn production process and the extra cost usually does not outweigh the increased risk. 

You can easily order mother spawn in bags by going to our website and selecting your strain(s) in our webshop.

Important: If you choose to multiply our spawn into a next generation of spawn, we do not give you any guarantee as you are not using our products for their proper purpose.


Yes, it is possible but you will have to send us a request, so we can send you a quote.


That hinges entirely on your own preferences and work method.

There are a number of qualities that a good spawn bag needs to have:

  1. Breathability / filtration: the bag needs to breathe without letting contaminants in, without drying out the substrate
  2. Resistant: the bag needs to be sufficiently strong to survive manhandling
  3. Heat and cold resistance: the bag needs to be sterilisable to 121°C (249,8°F) and coolable to 0°C (32°F)
  4. Size: there needs to be enough space inside, without it being too large
  5. Price: as most spawn bags are single-use, the price should be as low as possible
  6. Ecology: the bag should produce as little waste as possible.

NOTE: There are many types of receptacles on the market, from bottles to containers, vessels and bags, but most professional spawn producers use breathing bags. 

Having problems in selecting your ideal breathing mycelium bags? Then use Sac O2’s “bag finder” to guide you in finding your perfect fit. Visit the website on and set your filter tags.



NoSpores are not used in spawn production.

Their small size makes them difficult to handle, their genetic characteristics are slightly different from those of their parents, and they need time to germinate.Working with spores would be very risky in terms of results.

Our recommendation is to start with mother spawn to be sure of the starting point of your spawn production process. You can easily order them by selecting your strain(s) in our webshop.

This is indeed essential if you wish to be a successful producer. You will have to take a great deal of precautionary measures, that are for the largest part equal to the GMP (Good Manufacturing Practices) of any cleanroom environmentSome measures however are very specific to our needs, such as the sterilisation of filtered bags.We distinguish 2 main topics:

  1. Removing contaminants
  2. Preventing contaminants from entering the lab

Let us explain them briefly:

Removing contaminants

  • Sterilise all equipments and products in an autoclave. All materials that cannot be sterilised should be cleaned thoroughly as described in the FAQ below “What do you consider the correct procedure for cleaning?”
  • Clean the cleanroom daily and more extensively weekly and even more extensively every so often. Follow the procedure as described below in the FAQ below “What do you consider the correct procedure for cleaning?”
  • If and where necessary, use CIP (Cleaning In Place) techniques or disinfection methods such as UV light.
  • Finally, make sure that any contaminated product is immediately taken out of the laboratory and destroyed to avoid spreading spores of mould throughout the laboratory.

Preventing contaminants from entering the lab

  • Use the correct dressing protocol for the workers
  • Install a strict protocol for the product flow and for the movements of the workers
  • Using a top quality bag for your products
  • Using top quality equipment with stainless steel surfaces, good quality sealing machines, etc
  • Filter incoming air through HEPA filtersApply filtered overpressured air to your rooms, especially to your cooling rooms, inoculation rooms and the complete mother spawn department. Ideally, all stages of incubation receive overpressurized pure air too.
  • Filter the air around any extra sensitive manipulations with a laminar flow cabinet. Examples are the workbench where you inoculate manually, the entry and sampling ports of liquid containers, the place where bags are filled or redistributed, etc. The air from these workbenches is filtered to zero contamination and is then diffused in a laminar flow towards the user. It creates an extra safe working space in the cleanroom.
  • Check the workings of all Hepa filters at least once a year.

If you need a profound understanding, follow a spawn course.

Cleaning is indeed of the highest importance.

You must be meticulous, even to the point of becoming obsessive, or you will fail.

Follow these basic rules at the end of each working day and extend where needed:

  • First have a superficial cleaning to remove most of the organic matter that facilitates the multiplication of micro-organisms and to destroy some of the biofilm. It is in and under this biofilm that the multiplication of contaminants takes place, which will not react to disinfection products in the next step. Destroying this biofilm is the most important phase of the cleaning and disinfection process in a laboratory. It is really important to have appropriate and good tools to achieve this properly.
  • Then disinfect all surfaces and materials of your lab. This phase should also remove all remnants of the biofilm, so that the disinfectant can do its work.
  • Proceed to the rinsing of surfaces and equipment with (chlorinated) water or equivalent. This rinse will remove remaining particles, remove detergent residues (and sanitise surfaces through the chlorine action)
  • Then proceed to the disinfection of all other surfaces by either 1) wiping surfaces and equipment with a disinfection solution or 2) by spraying disinfectant on surfaces and equipment or 3) by soaking equipment in a disinfectant or 4) by fogging the room.

If you need a profound understanding, follow a spawn course.


Substrate and compost

We can distinguish two groups of cultivable mushrooms:

  1. Compost mushrooms, such as Agaricus bisporus, are cultivated on mushroom compost, a selective pasteurized substrate on which almost no other microorganisms can grow.
  2. Lignicolous mushrooms, including most exotic mushroom species, are cultivated on mushroom substrate. A number of species is grown on sterilized substrates, while other kinds are grown on selective, low-temperature pasteurized substrates.


But these terms are vague. A “substrate” for example can mean many things. In essence, we could say that  in mycelium cultivation, it is “the natural environment in which a fungus lives”.

In other words: it can also be used as a name for a spawn carrier, for the material a compost is made of. This can at times be confusing.

Our recommendations:

  1. Compost mushrooms: 7 to 10 litres used for each metric ton of Phase I compost.
  2. Lignicolous mushrooms on sterile substrates0,5 to 1% (WW/WW)
  3. Lignicolous mushrooms on pasteurised substrates2% to 8% depending on the strain and the recipe ( see technical information linked to articles on the website shop)
  4. Lignicolous mushrooms on logs with grain spawn: depending on the log diameter and personal inoculation system: Estimate: 5 liters of spawn per metric ton of wood.
  5. Lignicolous mushrooms on logs with plugs (dowels): depends on the size of the logs. The inoculation points should be 10 to 15 cm apart. So a log of 1 meter length and 20 cm thickness will have 3 rows of 7 plugs = 21 plugs.

The ideal storage temperature for most strains of spawn is 0 to 2°C. 

At this temperature the spawn can be kept for 2 to 4 months. If your fridge does not reach this temperature, but only 5°C for example, the shelf life of your spawn will decrease.

Place the boxes or bags on wire shelves, or stack them in an alternating manner like bricks, always being sure to leave ± 3 cm space for air flow between the boxes.

If spawn for Oyster Mushrooms or other exothermic species has to be stored for longer periods (more than 5 days), then spawn bags should be taken out of the boxes and put separately on shelves in the cold storage unit, this will help to keep the spawn in the best conditions to not accelerate its ageing.

On a daily basis, the cold storage unit should be opened for ventilation. Good air circulation is very important for uniform refrigeration and spawn survival.


  • There are a few exceptions like for example Pleurotus salmoneo-stramineus & Agaricus subrufescens (A “blazei”) spawn, which should be kept at ± 10°C.
  • Another exception are “spawn plugs” or (dowels): they can be kept much longer, at the same temperature of 0°C to 2°C. Depending on the strain, plugs can be kept for 8 months to 1 year. In order to improve spawn storage and to prevent overheating, never store complete pallets in the cold storage unit.
  • Some species, like Inonotus obliquus, or Stropharia rugoso-annulata for example, keep well in a fridge. Up to 1 year in extreme cases.

Spawn is a living product and should be stored cold for as short as possible.

But older spawn may still be fine and there are ways to test this quality.

Does the spawn look and smell good? If the bag is full of brown stinking liquid, the material is decaying and should be discarded. If it is clear, non-odorous yellow liquid, it is a sign of age, but it may still be active enough (example Pleurotus sp.).

How to test your spawn?

  • Use sterile petridishes with a rich medium, for example malt extract agar (MEA+), open the lid as little and as fast as possible in a LAF (Laminar Air Flow).
  • Put a few kernels on the agar plate in the best possible hygienic conditions.
  • Close the lid and roll the kernels around a bit to spread the mycelium.
  • Tape off the Petri dish with Parafilm and put it at room temperature.
  • If white mycelium filaments are visible at the edges of the grains in a matter of 3-5 days, your mycelium is still active and is fine.
  • If it starts growing after 1-2 weeks, it is getting old and may not be active enough to compete with other contaminants present in the substrate. It is better to be safe than sorry – the recommendation is to increase the spawn ratio at that point.


Looking for MEA or MEA+ test petridishes? You can order them with your spawn order in our webshop – only for sale if you are ordering mycelium products too.

We don’t put an expiry date on our spawn. 

We know some producers do, but we don’t because it is hard to make such claims if we have no control over the cold chain at the customer’s location.

But on average, grain spawn can be kept for 2 to 4 months at 0°C to 2°C with good ventilation and storage conditions.

Other recipes have different expiry dates. Spawn plugs or sawdust spawn for example can be kept much longer. But remember: the quality of spawn (every recipe) goes down as it ages. 

Use your spawn as fresh as possible!

It is recommended to test aged spawn on a petri dish before use.

See this FAQ for a manual how to do this.


The first thing to do is to find out what causes this wet spot.

  • Do you see any liquid coming out of the spawn bag?
  • Can you see a hole in the bag?
  • Is the bag hot to the touch?

If the answer to all these questions is NO, don’t be worried. Your box got wet by something else.

For example: the box was put in a puddle, or there was some external condensation on the spawn bag.

If the answer to one of these questions is YES, then the recommendation is not to use it. Contact us and send us a few clear pictures. There may be a problem with the spawn and we’ll need to find out what happened.


No, you should try to avoid that.

It is possible, but the ageing process speeds up and decreases the spawn quality. 

There is also an extra risk of overheating, especially in fast-growing species such as Pleurotus ostreatus.

If you really have no choice: do it, but it will be at your own risk.


No, it is not.

What is important to consider is the hygienic conditions in which the spawn bags will be stored prior to spawning. This is much more important than warming it up.

The worst possible scenario is a warm spawn bag in a contaminated environment. The contaminants will stick to the surface of the bags and infect your substrate.


No, you can not.

Substrates of some species can indeed be frozen, but spawn should not.

Spawn must be conserved under the best possible conditions without damaging it, is to store it proprely in a fridge at 0°C to 2°C. Temperatures below 0°C will affect the quality and the performances of the spawn, freezing damages some or even all of the mycelial cells.

When we freeze mycelium, we use a different technology. If this interests you, join a spawn course.


Spawn is a living product and should be stored cold for not too long.

But older spawn may still be fine and there are ways to test its quality.

Check this FAQ for more information on how to do this.

Sure you can (if the mushrooms are not a completely different species of course!).

Primordia are nothing more than an aggregate of mycelium filaments, each of which is identical to the mycelium on the kernels. Primordia only form on healthy spawn of mainly Pleurotus species, mostly as a result of temperature fluctuations.

This is a difficult question to answer, because it will depend on many secondary questions:

  • For which mushroom species?
  • What quantity?
  • Local production?
  • Can you get good quality spawn?
  • Etc

Before you start with your production, make sure to follow a training with us. We will be able to answer these questions during the course.

This is an extremely difficult question to answer.

Possibly even the most difficult one you could ever ask. Finding a contamination source can be exceptionally tricky.

When we consult farms in analyzing the problem, we ask hundreds of questions:

  • Which mushroom species?
  • Which type of substrate?
  • What is your production system?
  • Do you have a laminar air flow?
  • Where do you get your spawn and how do you store it?
  • Etc

In order to help you answer your questions and assess the risks related to your production, make sure to follow a training with us. We will be able to answer these questions during the course.

This is a complicated question to answer, because it will depend on your production system, your species, etc.

If you are producing sterilised substrates, there are a number of qualities that a good substrate bag needs to have:

  1. Breathability / filtration: the bag needs to breathe uniformly without letting contaminants in
  2. Resistance: the bag needs to be sufficiently strong to survive manhandling
  3. Heat and cold resistance: the bag needs to be sterilizable or pasteurizable, and must withstand cooling (and sometimes even freezing)
  4. Size: there needs to be enough space inside, without it being too large
  5. Price: as most bags are meant for single-use, the price should be as low as possible
  6. Ecology: the bag should produce as little waste as possible. There is no set rule as to which receptacle is best to use, although most professional substrate producers use bags.

There are quite a few good breathing bags on the market for such substrate production. In 2022, Sac O2 is launching a completely new production line for this application.

But additionally, there are production systems that have completely different requirements. For some systems, the bags do not contain a filter (filter introduced by the producer, holes taped off, …), for bottle productions there are completely different solutions again and for pasteurised substrate blocks the best solution is to form-fill with perforated plastics.

As far as we know, there are no equivalent alternatives available.

Heat treatment is a form of hygienisation: it is an essential measure of protection against insects, infections and diseases.

Different types of heat treatment can be used in substrate production.

Some producers sterilise at 121°C (249,8°F) and 1 bar (14,5 psi) overpressure. This is sterilisation sensu strictu. Sterilisation removes all living organisms from the substrate but steam under pretty high pressure is needed to reach this temperature and pressure.

Others use lower temperatures = pasteurisation. At these lower temperatures, some bacteria survive. The lowest possible temperature is 65°C (149°F). Below 65°C, fungal spores survive and heat treatment is of little use. But any temperature between 65°C and 121°C is possible. High pressure sterilisation (121°C), low pressure “sterilisation” (100-110°C), pasteurisation by steam or hot water immersion. Some producers call anything between 75°C and 120°C “Semi-sterilisation” or “Super-pasteurisation” but these terms have not (yet) been universally accepted, so be careful when using them. Hot water immersion is a form of pasteurisation, which is still different from steam pasteurisation.

There are other pasteurisation and sterilisation techniques such as gamma-irradiation, ozone treatment, cold pasteurisation with hydrated lime, etc, but none of these techniques has been proven to be equivalent to above mentioned heat treatment techniques.

If you wish to understand this to a deeper level, we would advise you to follow the spawn production group training.

We don’t advise this technique for continuous and large-scale production, but there are growers who use it with success.

It is a great technique for small-scale productions and for testing purposes. We use it ourselves in our R&D department for a “quick run” for example.

There are not so many mushroom species that can be inoculated this way with a good chance of succes.

Pasteurized straw could grow Stropharia mushrooms, or perhaps even Oyster mushrooms, or other fast Pleurotus species like Pleurotus florida.


There is no “best”.

You have to work with your locally available raw materials.

There is no use duplicating a recipe with hemp fibers if you have no access to hemp fibers, for example. If you want to learn about substrates and recipes the recommendation would be to follow one of our group trainings on substrate & wood fungi production.


Depending on the strain, you can indeed store fully incubated substrate in a freezer. This works particularly well for Shiitake blocks, for example.


You need a lot of enthusiasm and a good deal of knowledge.

Mushroom growing is not as easy as you might think.

Be aware of the fact that you will have to deal with microorganisms, small margins, hard work and a very perishable product.

We would strongly advise you to follow a training with us.

No. We can not guarantee mushroom yield and quality.

Our technical data sheets (see strain list) are a compilation of data provided by customers from different regions.

It is a general rule in mushroom cultivation that the results entirely depend on the way you treat the mycelium:

    1. Type and treatment of substrate
    2. Type of bag
    3. Quality of spawn at the time of inoculation
    4. Inoculation rate
    5. Climate in the incubation/ maturation rooms
    6. Climate control during fructification
    7. A number of other factors influences also the yield and the aspects of the mushrooms.

As a result, it is impossible to ” guarantee” yields and / or the efficiency.

Yes we do.

The most cultivated White Button Mushroom strain worldwide is available in the public domain. In other words: it is nobody’s property. We sell it under the number 7215.

There have been numerous attempts to come up with a better strain, but nobody has been succesful so far (not for lack of trying).

This strain is however extremely sensitive to degeneration and instabilities; maintaining its strength and vigour is truly a work for specialists.

No. If you wish to cultivate A. bisporus successfully in your climate all year round, the only option you have is to invest in climatised rooms, preferably “Dutch” style.

Otherwise, you can only produce in the “cold” season.

This is a very difficult question, that even the most skilled spawn producer will have trouble answering.

Degeneration is not a very well understood problem. Degenerations are random and can affect any part of the DNA of a mushroom, at any stage of the development. It can also show in any possible way in the production.

Known examples are clustering in Agaricus bisporus, or stroma in Pleurotus ostreatus. It can also be a gradual decrease in rentability, or in incubation delay. Viruses can also affect degenerations.

If you have suspicions, there are a number of things you can look into:

  • did the problem occur in multiple (spawn or substrate) batches, over different production days?
  • Does it lead back to a specific production “line”?


Make sure to collect production data like inoculum used in the production of substrate, production day, batch size, etc. Without a good traceability system, it is impossible to claim degeneration.

Our range of truly (sub)tropical species consists of:

A little info on the cultivation of these species:

    • The Paddy Straw Mushroom is the easiest to grow, but the mushrooms perish quickly, after 2-3 days.
    • The Split Gill is interesting to grow, but as far as we know, the mushroom is not really consumer accepted except for some regions in Central Africa.
    • The Milky Mushroom and Agaricus subrufescens require some skill. They are both compost mushrooms.


Most highly productive Oyster Mushroom strains grow naturally in moderate climate forests, such as we have in Western Europe. None of our classical Pleurotus ostreatus strains is successful when the minimum night temperature rises above 20°C.

But we have the following exceptions that can be grown in the (sub)tropics:

  • Pleurotus ostr. var. florida (M 2125) loves the substropical climate of Florida. But even this subspecies needs minimum night time temperatures below 23°C to start the pinhead formation.
  • The same is true for Pleurotus pulmonarius (M 2204) the Pink Oyster Pleurotus salmoneostramineus (M 2708) and the Yellow Oyster Pleurotus citrinopileatus (M 2502).
  • The only truly tropical Pleurotus species in our strain list which supports temperatures up to 30°C is Pleurotus cystidiosus (M 2800). But its yield is inferior to the above mentioned Pleurotus species and as a result, nobody really grows it.

If you want to try this, remember that it is often difficult to get them to form primordia and pinheads = to make them fruit.

In order to make them form primordia in a warm climate, the night temperature has to drop. This temperature drop will shock the Pleurotus species into forming pinheads. Once the pinheads have formed, they will usually keep growing. Hence, we speak of a minimum night time temperature.

There are not many other species that grow very fast, invasive and that are capable of keeping out competitors on pasteurised substrates. Oyster Mushroom is one of the only ones which can do that.

On the other hand, who told you that it was easy to cultivate? This is a common misunderstanding.

But it is true that it is one of the easiest strains to grow and definitely the fastest edible mushroom strain we have.

Other fast species:

    • The M9726 Ganoderma lucidum is a good strain for mycomaterials and is very quick.
    • The M9911 Trametes versicolor is also very fast, for medicinal purposes.

There are two options:

    • The Pleurotus ostreatus var. florida
    • The Pleurotus pulmonarius

The florida is better for solid fruiting bodies, but the pulmonarius can fruit at slightly higher temperatures (night time temperature maximum 22-23°C).

Try our 2603, it’s a great strain.

Nobody does it as far as we know.

It can be done with the Pleurotus eryngii var. ferulae, but has not been done frequently (yet). As a result, it has not been developed much. Until further notice, we advise against it.

Not really.

If you want our advice: Shiitake strain 3770 and Pleurotus strain 2191 are great strains for log cultivation.

A strain that performs well indoors will usually perform well outdoors.

Outdoor growing is even more forgiving than indoor, intensive cultivation. For example: every Shiitake strain that does well on substrates does well on wood logs. Many Shiitake strains that don’t do well on substrates, do well on logs. The same principle applies to the fast growing Pleurotus strains.

In Japan, China and other countries, they often heat treat their logs, that is correct.

But they are pasteurized, not sterilized.

In order to sterilise logs, you have to heat them up for a long time in order to get 121°C at the core of each log. Too long to be economical or ecological.

In addition, this is extremely difficult to measure (how will you get a probe inside these logs? Each log is different, which one will you measure?).

When you heat treat them, pasteurise them. Steaming is the most efficient way for heat transfer. You will kill off all fungi, which are your worst enemy.

The production method of is based on the same principles as mushroom production anywhere and it requires a good deal of microbiological insight, combined with simple cleverness and an open mind.

Look: logs cannot be fully standardized, on the contrary. The beauty about logs is that they are a pure product, straight from nature.

Sure, no problem. They can keep up to 1 year after production.

Seal the bag in half first and then cut it. Later on, we will post a little instruction video on how to do this.

No, they will be fine.

On one condition: you inoculated them with a strain which naturally grows in a climate where frost is part of the deal.

Yes you can, but we strongly advise against it. How would you ever control the growing parameters and keep diseases limited?

Mushroom color is defined by the DNA, but the intensity of the color has to do with the growing conditions that you give them.

The higher the temperature and the less light they are subjected to, the paler the fruiting bodies will be.

A Pleurotus ostreatus for example can be dark grey, dark blue, light grey, white, brown, to brownish yellow. All the same strain.

You can influence the size and shape of your mushrooms by playing with the growing parameters.

High CO2 for example will stimulate a large stem and a small cap, or a long stem and a small cap. Similarly, you can play with temperature and humidity to a certain degree.

That is probably caused by a too high level of CO2 in the growing room. Unless if you want to grow larger stems (such as often done with King Oyster Mushrooms), the quality of Oyster Mushrooms goes down as the CO2 concentration in the room goes up.

    • With 800 ppm and more, the stems start to stretch and the caps become smaller.
    • 600 to 700 ppm is a good compromise.

It is important that this CO2 concentration is reached through constant air movement, and not through intermittent pulses. Otherwise, the CO2 concentration will still go up too much and the caps will dry out.

Alternatively, you could always try selling your “Trumpet Oysters” for double the price.

This is a very difficult question, that even the most skilled producer will have trouble answering.

Degeneration is not a very well understood problem. Degenerations are random and can affect any part of the DNA of a mushroom, at any stage of the development. They can also show in any possible way in the production.

Known examples are clustering in Agaricus bisporus, or stroma in Pleurotus ostreatus.

It can also be a gradual decrease in rentability, or in incubation delay. Viruses can also affect degenerations.

If you have suspicions, check this out:

  • Did the problem occur in multiple (spawn or substrate) batches, over different production days?
  • Does it lead back to a specific production “line”?
  • Are your colleagues experiencing the same issue?


Make sure to collect production data like inoculum used in the production of substrate, production day, batch size, etc. Without a good traceability system, it is impossible to claim degeneration.

That depends on your hygienisation method.

If you are only relying on the heat treatment provided by the short steaming in your coffee machine, you will be limited in the selection of strains you can use.

These are your only options:

  • Winter Oyster Mushroom (Pleurotus ostreatus)
  • Summer Oyster Mushroom (Pleurotus pulmonarius)
  • Florida Oyster Mushroom (Pleurotus ostreatus var. florida)
  • a few fast-incubating wood fungi such as Trametes versicolor and Schizophyllum commune.
  • if you’re lucky, you may try a Pink or Yellow Oyster Mushroom. But expect erratic results.


If you include an extra pasteurisation step at 95-105°C for at least 30-50 minutes and on the condition you have good control over the quality of your raw materials, you should be able to grow a whole range of species. In that case, you are not limited really.

There are not so many mushroom species that can be inoculated this way with a good chance of succes.

Pasteurized straw could grow Stropharia mushrooms, or perhaps even Oyster mushrooms, or other fast Pleurotus species like Pleurotus florida.

Yes, we do indeed.

We are working closely together with Chaga OÜ from Estonia on the development of a potent strain for outdoor, extensive cultivation.

    • Our plugs have a very high success ratio, close to 100%.
    • The time-to-harvest depends on your location, but it can be less than 5 years.
    • The chaga conk can be harvested and a new conk will emerge from the tree.

We do have glow-in-the-dark mycelium, but it is only visible if you’re in a dark room and if your eyes get accustomed to the dark for at least a minute. Even then and even with a fresh mycelium, the glow is weak.

If you still want to see more glow, watch the movie Avatar.