How to Use Our Grain Myceliums?
🌱 Introduction: How do mushrooms grow?
Unlike plants that feed by photosynthesis, mushrooms decompose organic matter. For the mycelium to fruit (produce mushrooms), it needs a substrate, that is, a material that serves as its food. The quality and preparation of this substrate are crucial to obtaining an abundant and good quality harvest.
🍄 What is a substrate?
A substrate is a nutritional support on which the mycelium develops; it is its food. Choosing the right substrate is essential because it directly influences the colonization speed, the quality of the mushrooms, and their yield. Here are some examples of commonly used substrates:
- Straw: Fiber-rich, ideal for pleurotes. It must be pasteurized before use to eliminate contaminants.
- Wood sawdust: Perfect for shiitakes and other lignicolous mushrooms. Prefer hardwoods (oak, beech) for better results.
- Straw or wood pellets: Convenient and easy to store, they are often pre-pasteurized, simplifying preparation.
- Cardboard: Low cost and easy to find, it is used for cultivating robust varieties like pleurotes.
- Coffee grounds: Nutrient-rich, particularly suitable for urban cultivation and small-scale growing.
The choice of substrate depends on several factors:
- The mushroom variety: some prefer substrates rich in cellulose (pleurotes), others in lignin (shiitakes).
- The growing conditions: indoors, sterilized or pasteurized substrates are often preferred to avoid contamination. Outdoors, less processed substrates can be used.
By understanding the needs of the mycelium and choosing the right substrate, you maximize your chances of success in your cultivation.
📑 Table of Contents
1. How to use our grain spawn? 🧪
- Choose your substrate: Select a substrate suitable for the mushroom variety (straw for pleurotes, sawdust for shiitakes, etc.). Our optimal substrate works well for most varieties on our site.
- Prepare the substrate: To limit contaminations, pasteurize (heat) or sterilize (pressure cooker) your substrate according to the recommended method.
- Inoculate the substrate: Once the substrate has cooled, incorporate the grain spawn, distributing it evenly.
- Incubate: Place the mixture in a clean and controlled environment (20-25°C for oyster mushrooms), maintaining high humidity.
- Trigger fruiting: Once the substrate is fully colonized (whitish and compact), adjust light, humidity, and temperature to encourage the first mushrooms to appear.
Tip: Regularly check the state of colonization. If you observe green or black spots, these are probably contaminations (molds). To prevent contaminations from spreading from one bag to another, separate those that are contaminated.
🌾 Examples of Easy Cultivations:
1. Oyster Mushroom on Straw (Outdoor or Indoor Cultivation)
Oyster mushrooms are known for their rapid growth and their ability to colonize a wide variety of substrates, especially straw.
- Substrate: Chopped straw or straw pellets.
- Preparation: Soak the straw in hot water (75°C) for 1 hour to eliminate contaminants.
- Inoculation: Once cooled, mix 5 to 10% of grain spawn with the moist straw.
- Incubation: Place everything in perforated bags or buckets with holes, at 20-25°C, for 2 to 3 weeks.
- Fruiting: Expose the substrate to indirect light with 80-90% humidity.
Note: There is an alternative technique to heat pasteurization which is pasteurization with lime. To do this, use slaked lime (white limestone lime). Dilute one cup for about 50 liters of water.
Soak the straw overnight (12h) in this lime water. This will allow the straw to moisten and raise its pH (=alkalinize), which will create an environment unfavorable to the development of bacteria or molds and rather favorable to the development of oyster mushroom mycelium.
You can also use our organic straw pellets, which are already pre-pasteurized and very suitable for oyster mushroom cultivation.
2. Shiitake on Sawdust (Indoor Cultivation)
The shiitakes are lignicolous mushrooms that ideally develop on a sawdust substrate.
- Substrate : Hardwood sawdust (oak, beech).
- Preparation : Mix the sawdust with boiling water to reach about 60% moisture.
- Inoculation : Once cooled, add 10% of grain spawn.
- Incubation : Maintain at 20°C for 10 to 12 weeks, in filter bags.
- Fruiting : After colonization, remove the bag and place in a humid environment (15-18°C).
Tip : To encourage shiitake fruiting, create a thermal shock by placing the colonized block in a cool place (4°C) for 24 hours.
2. The Importance of Working Cleanly
Cleanliness is a key success factor in mushroom cultivation. Whether you work in a laboratory or an outdoor environment, maintaining clean working conditions will minimize contamination risks.
Classic question: "Yes, but in nature, mushrooms grow on their own, so why should I pasteurize or sterilize my substrates?"
In nature, mushrooms grow without human intervention, but conditions are unpredictable and hostile: insects, molds, bacteria, drought, frost, UV... Only the strongest survive, hence the production of millions of spores hoping to fruit.
In controlled cultivation, the goal is to maximize success chances. Pasteurization reduces contaminants, allowing the mycelium to quickly colonize the substrate. Working cleanly avoids adding pests and is essential for sensitive varieties.
In summary, cleanliness and pasteurization ensure safer and more productive crops compared to natural conditions.
A. Working Conditions for Resistant Varieties
Some varieties, like oyster mushrooms, are more tolerant of non-sterile working conditions. If you work with a substrate low in sugar and nitrogen, such as straw, the contamination risk is low. In this case, pasteurizing the substrate is sufficient and you can inoculate it in open air. However, even under these conditions, cleaning surfaces and tools is recommended.
Tip : If you work outdoors, inoculating after rain can reduce contamination risks. Rain cleans the air and decreases the number of airborne particles, creating a purer environment for inoculation.
B. Working Conditions for Sensitive Varieties
For more demanding varieties, such as shiitakes or lion's manes, which require an enriched substrate, more thorough pasteurization or sterilization is necessary. Working under sterile conditions is essential to avoid contaminations that could compromise the culture.
Home tip : When sterilizing an enriched substrate in a pressure cooker, open the cooled bag in as clean an environment as possible. Place the mycelium on the surface of the substrate without mixing it immediately.
This technique gives the mycelium a competitive advantage over potential contaminants that come into direct contact with it. Incubation is slightly longer than without mixing, but the risk of contamination is greatly reduced.
C. Cleaning the bag
When using mycelium in the laboratory, it is essential to maintain strict sterile conditions to avoid any contamination.
Steps to follow :
- Clean the outside of the mycelium bag with a 10% bleach solution or 70% alcohol.
- Break and crumble the mycelium by gently massaging the bag, taking care not to tear it.
- Sterilize the blade of a scalpel by heating it in the flame, then open the bag.
- Gradually pour the contents of the bag into the sterile substrate, avoiding any contact between the edges of the bag and the inside of the container holding the substrate.
Recommendation : It is preferable to use the entire contents of the bag at once to minimize the risk of contamination. If this is not possible, reseal the bag as cleanly as possible and reuse it quickly. However, our experience shows that this increases the risk of contamination.
3. Optimal Storage of Mycelia
Our grain spawn are living products, sensitive to time and storage conditions. Upon receipt, it is imperative to use them as quickly as possible to preserve their vigor and minimize the risk of contamination.
Why is speed essential?
Mycelia are composed of active fungal cells that continue to grow and develop even after the complete colonization of the grains. The shorter the time between receipt and use, the more vigorous the mycelium is and the more capable it is of effectively colonizing the substrate.
Anticipation of production lead times When ordering, it is important to consider a production lead time that can vary between 1 and 4 weeks. To ensure delivery at the right time, we advise you to place your order in advance and, if necessary, specify the desired delivery date in the comments during payment. This allows you to have fresh grain spawn ready to be used upon receipt.
A. Storage Temperature
Ideally, mycelia should be stored in the refrigerator at a temperature between 1 and 5°C. This temperature range slows mycelium growth without damaging it, thus extending its lifespan up to 4 weeks.
For mycelia of exothermic varieties, such as oyster mushrooms, it is particularly important to space the bags in the refrigerator to allow sufficient air circulation and even cold distribution.
B. Precautions for Long-Term Storage
For prolonged storage, you can cover the filter with adhesive tape. This precaution reduces air entry and thus limits the introduction of potential contaminants through the filter. However, even with these precautions, we recommend using them within 3 to 4 weeks, as mycelium viability decreases over time.
Factors influencing the lifespan of mycelia :
- Strain: Slow-growing strains have a longer lifespan.
- Storage temperature: A stable and low temperature is essential to extend shelf life.
- Storage conditions: Good air circulation and spacing of bags contribute to optimal preservation.
Signs of mycelium aging :
- Compaction of the mycelium, making it less friable.
- Appearance of crusts or clumps on the surface of the grain.
- Production of colored liquid, sometimes foul-smelling, a sign of degradation.
- Autolysis of the mycelium, leading to product degradation. At this stage, it is no longer usable.
How to identify usable mycelium?
Even if the mycelium shows signs of aging such as compaction or crust formation, it can still be used. However, it is best to use it before the appearance of colored liquids, a sign that autolysis has begun.
Degeneration and Generations in Mycology
Tracking mycelium generations is essential to ensure the vigor, productivity, and stability of fungal cultures. Each stage – from the Petri dish to liquid culture, then to the mother grain, to the grains, and finally to the substrates – corresponds to a generation (G0 to G4).
Degeneration is talked about when a mycelium loses vitality, develops morphological abnormalities, or becomes less efficient in fruiting. Contrary to popular belief, this degeneration is not only related to the number of successive duplications. It is often favored by a lack of nutritional diversity, a poor substrate, or even a lack of physiological activity of the mycelium when it remains inactive for too long.
Maintaining a good level of stimulation (exposure to a favorable environment, renewal of varied substrates, good growth rate) allows the mycelium to retain its vigor longer, even after several generations. Good genetic traceability monitoring (e.g., generation G2, G3…) is therefore essential to avoid strain exhaustion and ensure quality harvests.
4. Amount of Mycelium to Use Relative to the Substrate
The amount of mycelium to use depends on the cultivated variety and the type of substrate. Here are some recommendations based on our experiences:
- Oyster mushroom on straw: Use about 10% mycelium relative to the weight of the wet substrate.
- Shiitake on sawdust: A similar or slightly higher proportion is recommended.
- Stropharia in the garden on straw: In non-sterile outdoor conditions, increase the proportion to about 20% grain spawn.
Under sterile laboratory conditions, it is possible to reduce the amount of mycelium to 2-3%, or even 1%, of the substrate weight. However, in an outdoor or less controlled environment, a higher amount of mycelium is necessary to minimize contamination risks.
Why is this important?
Using an insufficient amount of mycelium increases the risk of contamination, as the mycelium will take longer to colonize the substrate, leaving room for other organisms to settle.
Grain spawn can also be seen as a way to enrich its carbon substrate, and thus a larger amount of mycelium will potentially increase the productivity of the bags.
6. Mycelium Viability Test
If you have doubts about the viability of your mycelium, it can be tested in various ways:
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Incubation at Room Temperature : Keep the bag of grain spawn at room temperature (around 20°C) for 5 to 10 days. The mycelium should continue to grow and cover the grains.
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Petri Dish Test : You can also take a small amount of spawn and spread it on a pre-poured Petri dish. Observe the development of the spawn over several days.
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Wet Cardboard Test : Pasteurize a piece of brown cardboard for 30 seconds in boiling water, drain it. Place a small sample of spawn on the cooled cardboard piece. The spawn should start colonizing the cardboard within 5 to 10 days if it is viable.
Note: the appearance of the spawn can vary from one variety to another. For example, it is normal that lion's mane spawn is not as white and dense as oyster mushroom spawn. The smell and color can also vary depending on the varieties, and this is normal.
If it seems that the spawn is not sufficiently visible upon receipt of your package, it is probably because it was shaken during transport and the grains have separated, which is not a problem in itself. The spawn is indeed present inside the grains and can be used as is. You can also choose to incubate it for a few days at 20° to see the spawn fuse the grains again, indicating its vigor.
If you have any issues with one of our spawn, do not hesitate to contact us.
7. Our quality guarantee
Our spawn, or "mushroom whites," are seeds cultivated on grains intended for substrate inoculation. Here is some additional information about our practices and products.
Local production and guaranteed quality
All our spawn are produced in our laboratories in Gembloux, Belgium. We select our strains based on their vigor, natural disease resistance, taste quality, and productivity. We are inspected annually by Certisys for the organic certification of our spawn, substrates, and mushrooms.
Maintaining potential and vigor
We guarantee the purity and vigor of our strains through regular cultivation in non-sterile media, followed by reproduction in sterile laboratory conditions. This method maintains robust and high-performing strains, ready to inoculate your substrates successfully.
Production on order
We produce our grain spawn on order, with a production lead time of 2 to 3 weeks. This allows us to send you spawn at the peak of their vigor, directly after incubation, without storing them in the refrigerator. These conditions ensure better resistance to transport conditions.