How to Use Our Grain-Based Mycelium?
🌱 Introduction: How do mushrooms grow?
Unlike plants, which obtain their nutrients through photosynthesis, fungi break down organic matter. For the mycelium to fruit (produce mushrooms), it needs a substrate—that is, a material that serves as its food source. The quality and preparation of this substrate are crucial for a harvest , high-quality harvest .
🍄 What is a growing medium?
A substrate is a nutrient-rich medium on which the mycelium grows; it serves as its food source. Choosing the right substrate is essential because it directly affects the rate of colonization, the quality of the mushrooms, and their yield. Here are some examples of commonly used substrates:
- Straw: High in fiber, ideal for oyster mushrooms. It must be pasteurized before use to eliminate contaminants.
- Sawdust: Perfect for shiitake mushrooms and other wood-decaying fungi. For best results, use hardwood sawdust (oak, beech).
- Straw or wood pellets: Convenient and easy to store, they are often pre-pasteurized, which makes preparation easier.
- Cardboard: Inexpensive and easy to find, it is used for growing hardy varieties such as oyster mushrooms.
- Coffee grounds: Rich in nutrients, they are particularly well-suited for urban gardening and small-scale gardening.
The choice of substrate depends on several factors:
- The type of mushroom: some prefer substrates rich in cellulose (oyster mushrooms), while others prefer those rich in lignin (shiitake mushrooms).
- Growing conditions: Indoors, sterilized or pasteurized growing media are often preferred to prevent contamination. Outdoors, less processed growing media can be used.
By understanding the needs of the mycelium and choosing the right substrate, you’ll give yourself the best chance of a successful grow.
📑 Table of Contents
1. How do you use our grain-based mycelium? 🧪
- Choose your substrate: Select a substrate suitable for the type of mushroom (straw for oyster mushrooms, sawdust for shiitake mushrooms, etc.). Our standard substrate works well for most varieties available on our site.
- Prepare the substrate: To minimize contamination, pasteurize (using heat) or sterilize (using a pressure cooker) your substrate according to the recommended method.
- Inoculate the substrate: Once the substrate has cooled, incorporate the grain-based mycelium, distributing it evenly.
- Incubate: Place the mixture in a clean, controlled environment (20–25°C for oyster mushrooms), maintaining high humidity.
- Induce fruiting Once the substrate is fully colonized (whitish and compact), adjust the light, humidity, and temperature to encourage the first mushrooms to appear.
Tip: Check the condition of the culture regularly. If you notice green or black spots, these are likely signs of contamination (mold). To prevent contamination from spreading from one bag to another, set aside any contaminated bags.
🌾 Examples of Easy-to-Grow Crops:
1. Oyster Mushrooms on Straw (Outdoor or Indoor Cultivation)
Oyster mushrooms are known for their rapid growth and their ability to grow on a wide variety of substrates, including straw.
- Bedding: Chopped straw or straw pellets.
- Preparation: Soak the straw in hot water (75°C) for 1 hour to remove contaminants.
- Inoculation: Once cooled, mix 5 to 10% of grain-based mycelium into the damp straw.
- Incubation: Place everything in perforated bags or buckets with holes, at 20–25°C, for 2 to 3 weeks.
- fruiting Place the growing medium in indirect light with a humidity level of 80–90%.
Note: There is an alternative technique to heat pasteurization, which is lime pasteurization. To do this, use slaked lime (white limestone lime). Mix one cup with about 50 liters of water.
Soak the straw overnight(12 hours) in this lime water. This will allow the straw to absorb moisture and raise its pH level (making it more alkaline), which will create an environment that is unfavorable for the growth of bacteria or mold but conducive to the growth of oyster mushroom mycelium.
You can also use ourorganic straw pellets, which are already pre-pasteurized and ideal for growing oyster mushrooms.
2. Shiitake on Sawdust (Indoor Cultivation)
Shiitake mushrooms are wood-decaying fungi that grow best on a substrate of sawdust.
- Substrate: Hardwood sawdust (oak, beech).
- Preparation: Mix the sawdust with boiling water until it reaches about 60% moisture content.
- Inoculation: Once cooled, add 10% grain mycelium.
- Incubation: Keep at 20°C for 10 to 12 weeks in filter bags.
- fruiting After colonization, remove the bag and place it in a humid environment (15–18°C).
Tip: To encourage shiitake fruiting to fruiting , create a cold shoc placing the colonized block in a cool place (4°C) for 24 hours.
2. The Importance of Working Neatly
Cleanliness is a key factor in successful mushroom cultivation. Whether you work in a laboratory or an outdoor setting, maintaining clean working conditions will minimize the risk of contamination.
A common question: "Yes, but in nature, mushrooms grow on their own, so why shouldn't I pasteurize or sterilize my substrates?"
In nature, mushrooms grow without human intervention, but conditions there are unpredictable and hostile: insects, mold, bacteria, drought, frost, UV rays... Only the hardiest survive, which is why they produce millions of spores in the hope of bearing fruit.
In controlled cultivation, the goal is to maximize the chances of success. Pasteurization reduces contaminants, allowing the mycelium to quickly colonize the substrate. Working cleanly prevents the introduction of parasites and is essential for sensitive strains.
In short, cleanliness and pasteurization ensure safer and more productive crops compared to natural conditions.
A. Growing Conditions for Disease-Resistant Varieties
Some varieties, such as oyster mushrooms, are more tolerant of non-sterile growing conditions. If you are working with a substrate low in sugar and nitrogen, such as straw, the risk of contamination is low. In this case, pasteurizing the substrate is sufficient, and you can inoculate it in the open air. However, even under these conditions, it is recommended that you clean surfaces and tools.
Tip: If you're working outdoors, inoculating after it rains can reduce the risk of contamination. Rain cleans the air and reduces the number of airborne particles, creating a cleaner environment for inoculation.
B. Growing Conditions for Susceptible Varieties
For more demanding varieties, such as shiitake or lion's mane mushrooms, which require an enriched substrate, more thorough pasteurization or sterilization is necessary. Working under sterile conditions is essential to prevent contamination that could compromise the cultivation process.
Household tip: When sterilizing enriched substrate in a pressure cooker, open the cooled bag in as clean an environment as possible. Spread the mycelium over the surface of the substrate without mixing it in immediately.
This technique gives the mycelium a competitive advantage over potential contaminants that come into direct contact with it. Incubation takes slightly longer than without the mixture, but the risk of contamination is significantly reduced.
C. Cleaning the bag
When using mycelium in the laboratory, it is essential to maintain strict sterile conditions to prevent contamination.
Steps to follow:
- Clean the outside of the mycelium bag with a 10% bleach solution or 70% alcohol.
- Break up and crumble the mycelium by gently massaging the bag, taking care not to tear it.
- Sterilize the scalpel blade by heating it over a flame, then open the bag.
- Gradually pour the contents of the bag into the sterile medium, taking care to avoid any contact between the edges of the bag and the inside of the container holding the medium.
Recommendation : It is best 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 promptly. However, our experience shows that this increases the risk of contamination.
3. Optimal Storage of Mycelium
Our grain-based mycelium products are living organisms that are sensitive to time and storage conditions. Upon receipt, it is essential to use them as soon as possible to maintain their vitality and minimize the risk of contamination.
Why is speed so important?
Mycelia are composed of active fungal cells that continue to grow and develop even after the grains have been fully colonized. The shorter the time between receipt and use, the more vigorous the mycelium is and the more effectively it can colonize the substrate.
Estimating Production Lead Times When placing an order, it is important to factor in a production lead time of 1 to 4 weeks. To ensure timely delivery, we recommend placing your order in advance and, if necessary, specifying your desired delivery date in the comments section during checkout. This ensures that you receive fresh mycelium ready for use upon delivery.
A. Storage Temperature
Ideally, mycelium should be stored in the refrigerator at a temperature between 1 and 5°C. This temperature range slows the growth of the mycelium without damaging it, thereby extending its shelf life to up to 4 weeks.
For the mycelium of exothermic varieties, such as oyster mushrooms, it is particularly important to space the bags out in the refrigerator to allow for adequate air circulation and even distribution of cold air.
B. Precautions for Long-Term Storage
For long-term storage, you can cover the filter with adhesive tape. This measure reduces airflow and thus limits the entry of potential contaminants through the filter. However, even with these precautions, we recommend using them within 3 to 4 weeks, as the viability of the mycelium decreases over time.
Factors affecting the lifespan of mycelia:
- strain Slow-growing strains have a longer lifespan.
- Storage temperature: A stable, cool temperature is essential for extending shelf life.
- Storage conditions: Good air circulation and spacing between bags help ensure optimal preservation.
Signs of aging in the mycelium:
- Compaction of the mycelium, making it less crumbly.
- The appearance of crusts or lumps on the surface of the grain.
- The production of a colored, sometimes foul-smelling liquid, indicating deterioration.
- Autolysis of the mycelium, leading to product degradation. At this stage, the product is no longer usable.
How can you tell if mycelium is still usable?
Even if the mycelium shows signs of aging, such as hardening or crust formation, it can still be used. However, it is best to use it before colored liquids appear, as this is a sign that autolysis has begun.
Degeneration and Generations in Mycology
Tracking mycelium generations is essential to ensuring the vigor, productivity, and stability of fungal cultures. Each stage—from the Petri dish to liquid culture, then to the mother culture, cultures, and finally to the substrates—corresponds to a generation (G0 to G4).
Degeneration occurs when a mycelium loses vitality, develops morphological abnormalities, or becomes less effective at fruiting. Contrary to popular belief, this degeneration is not solely linked to the number of successive passages. It is often exacerbated by a lack of nutritional diversity, a poor substrate, or a lack of physiological activity in the mycelium when it remains inactive for too long.
Maintaining an appropriate level of stimulation (exposure to a conducive environment, regular renewal of diverse growth media, and a healthy growth rate) allows the mycelium to retain its vigor for longer, even after several generations. Careful tracking of genetic lineage (e.g., G2, G3 generations) is therefore essential to prevent strain depletion and ensure high-quality harvests.
4. Amount of Mycelium to Use Relative to the Substrate
The amount of mycelium to use depends on the variety being grown and the type of substrate. Here are some recommendations based on our experience:
- Oyster mushrooms on straw: Use approximately 10% mycelium relative to the weight of the moist substrate.
- Shiitake on sawdust: A similar or slightly higher proportion is recommended.
- Stropharia in the garden on straw: Under non-sterile outdoor conditions, increase the proportion of mycelium on grains to about 20%.
Under sterile laboratory conditions, it is possible to reduce the amount of mycelium to 2–3%, or even 1%, of the substrate’s weight. However, in an outdoor or less controlled environment, a higher amount of mycelium is necessary to minimize the risk of contamination.
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 take hold.
Mycelium on grains can also be seen as a way to enrich the carbon substrate, and thus a larger amount of mycelium could potentially increase the productivity of the bales.
6. Mycelium Viability Test
If you have any doubts about the viability of your mycelium, there are several ways to test it:
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Incubation at Room Temperature: Store the mycelium packet at room temperature (about 20°C) for 5 to 10 days. The mycelium should continue to grow and cover the grains.
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Petrishot Test: You can also take a small amount of mycelium and spread it on a pre-prepared Petri dish. Observe the growth of the mycelium over several days.
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Wet Cardboard Test: Pasteurize a piece of brown cardboard for 30 seconds in boiling water, then drain it. Place a small sample of mycelium on the cooled piece of cardboard. If the mycelium is viable, it should begin to colonize the cardboard within 5 to 10 days.
Note: The appearance of the mycelium can vary from one variety to another. For example, it is normal for lion’s mane mycelium not to be as white and dense as that of oyster mushrooms. The smell and color can also vary depending on the variety, and this is normal.
If it seems to you that the mycelium isn't clearly visible when you receive your package, it's likely that the package was shaken during shipping and the grains have separated—which isn't a problem in itself. The mycelium is still present inside the grains and can be used as is. You can also choose to incubate it for a few days at 20°C to see the mycelium fuse all the grains together again, indicating its vitality.
If you have any concerns about one of our mycelium products, please don't hesitate to contact us.
7. Our Quality Guarantee
Our mycelium, or "mushroom spawn," consists of grains used to inoculate growing media. Here is some additional information about our practices and products.
Locally produced and quality guaranteed
All our mycelium is produced in our laboratories in Gembloux, Belgium. We select our strains based on their vigor, natural disease resistance, flavor, and productivity. We undergo annual inspections by Certisys for organic certification of our mycelium, substrates, and mushrooms.
Maintaining Potential and Vitality
We guarantee the purity and vitality of our strains through regular cultivation in non-sterile media, followed by propagation in sterile laboratory conditions. This method ensures that our strains remain robust and high-performing, ready to successfully inoculate your substrates.
Made-to-order production
We produce our mycelium on demand, with a production lead time of 2 to 3 weeks. This allows us to ship mycelium at the peak of its vitality, directly after incubation, without storing it in the refrigerator. These conditions ensure greater resistance to shipping conditions.