Learn About The Best Mushroom Substrates for Mushroom Cultivation

Learn About The Best Mushroom Substrates for Mushroom Cultivation

A Guide to Mushroom Substrates for Mushroom Cultivation

A Guide to Mushroom Substrates for Mushroom Cultivation.

Introduction to Mushroom Substrates.

What is a Mushroom Substrate and Why is it Needed?.

The Most Common Mushroom Growing Substrates and How to Prepare Them.

Preparation of Grain-Based Substrates for Mushroom Cultivation.

Substrate Specificity for Mushroom Varieties.

Conclusion: Fostering Growth Beyond the Substrate.

Frequently Asked Questions:

Section Key Takeaways
Introduction to Mushroom Substrates - Substrates are vital for providing the right nutrients and environment for mushrooms to grow.
What is a Mushroom Substrate - A mushroom substrate is akin to soil for plants, essential for the growth and fruiting of mushrooms.
Common Mushroom Growing Substrates - Substrates must be chosen and prepared based on the specific needs of different mushroom species.
Grain-Based Substrates - Grain substrates like rye berries, wild bird seed, and red milo sorghum need sterilization before use.
Substrate Specificity - Matching the right substrate with the right mushroom type is crucial for optimal growth and yield.
Conclusion - Successful cultivation involves learning, experimentation, and community engagement.
FAQs - Sterilization and proper moisture are key to preparing substrates; spent substrates can be recycled.

Introduction to Mushroom Substrates

Mushroom cultivation is an art and science that fascinates hobbyists and commercial growers alike. At the core of this practice lies the mushroom substrate, a specific medium on which mushroom mycelium thrives. But what exactly is a mushroom substrate? Simply put, it is the nourishing ground or substance where mushrooms are grown. A substrate must provide the necessary nutrients and environment for mushroom spores to colonize and eventually develop into fruiting bodies that we recognize as mushrooms.

For those just starting out or looking to save time, we've done the hard work for you. Check out our selection of premade mushroom substrates, tailored for convenience without compromising on quality.

The Role and Definition of Mushroom Substrates in Mushroom Cultivation

The substrate plays a pivotal role in cultivation. Whether you are a seasoned mushroom grower or new to the mushroom cultivation scene, understanding that the substrate is akin to soil for plants is crucial. It's where the mushroom spawn, which is mixed with mushroom spores or mushroom culture, establishes itself. Mushroom species vary widely, and so do their substrate needs. While oyster mushrooms might thrive on a straw substrate, magic mushrooms may require a grain-based substrate for the best results.

What is a Mushroom Substrate and Why is it Needed?

In essence, a substrate is the foundation of mushroom grow efforts. It is not just a base but a source of water and nutrients. Some common substrates include coco coir, vermiculite, wood chips, and straw. These substrates can be used alone or in various combinations to create a substrate mix. The right substrate can greatly impact the mushroom fruiting quality and yield. For instance, straw might be a great substrate for one type of mushroom, but another may require the addition of nutrient supplements to the mix for best mushroom growth.


Choosing a Mushroom Substrate

The choice of substrate also depends on the cultivation method. A low-tech mushroom farm might opt for a straw substrate for its simplicity and cost-effectiveness, while a commercial operation may choose a more complex substrate recipe for higher yields.

The journey of a mushroom grower often involves experimenting with different substrates to find what provides the best results for their mushroom species. Therefore, understanding and choosing the best substrate is a critical step in the mushroom cultivation process.

The Most Common Mushroom Growing Substrates and How to Prepare Them

Selecting the right type of substrate is paramount for any mushroom cultivation endeavor. Each kind of substrate caters to different needs and is prepared differently to support the growth of various mushroom species. Here's a guide to the most common mushroom substrates, their preparation, and the mushrooms that typically flourish on them.

Pasteurized Straw as a Substrate for Mushroom Cultivation

Pasteurized Straw In Mushroom Grow Bag

For those looking to grow mushrooms, particularly species like oyster mushrooms, shiitake, lion's mane, and beech mushrooms, pasteurized straw serves as an excellent and suitable substrate. Here's a step-by-step guide to preparing pasteurized straw:

  1. Chopping the Straw: Begin by chopping the straw into shorter pieces, ideally around 2-4 inches in length. This size allows for better compaction and colonization by the mushroom mycelium. Shorter straw lengths also make for more manageable handling and easier sterilization of the substrate.

  2. Moistening the Straw: Moisten the straw with clean water until it’s evenly damp. The moisture is crucial because it will create the necessary environment for the mycelium to grow. Ensure that the straw is not too wet, as an overly saturated substrate can lead to problems such as lack of aeration and potential mold growth.

  3. Heating the Water: Fill a large container with water and heat it to a temperature range of 65-80°C. This is the optimal temperature for pasteurization, as boiling the substrate doesn't get it hot enough to sterilize, yet this range is sufficient to eliminate unwanted organisms.

  4. Pasteurizing the Straw: Submerge the straw in the hot water. Maintain the temperature range for 1-2 hours. This pasteurization process will kill any harmful bacteria and fungi, ensuring that the substrate doesn’t harbor any competitors that could impede mushroom growth.

  5. Draining the Straw: After pasteurization, remove the straw and let it drain. It’s important to allow the straw to cool down to room temperature before inoculating it with mushroom spawn. Excess water should be removed to prevent the substrate from becoming overly saturated.

  6. Inoculating the Straw: Once cooled, inoculate the straw with about 100 grams of mushroom spawn per pound of dry straw. Mix the spawn thoroughly to distribute it evenly throughout the substrate. This mix will give the mushroom an advantage and promote even colonization.

  7. Incubation: Place the inoculated straw in a grow bag or container and seal it with air filters to allow for gas exchange. Store the container in a dark, warm place where the temperature is stable. During this phase, the mycelium will colonize the substrate, which can take several weeks depending on the mushroom species.

  8. Monitoring Moisture Content: Throughout the colonization period, ensure the moisture content remains consistent. Water in the substrate is critical for mycelium development, but the substrate shouldn’t be soggy. If the substrate is too dry, lightly mist it with sterile water to maintain the necessary humidity.

By following these steps, even a novice mushroom grower can prepare a substrate for mushroom cultivation that is both effective and inexpensive. Once the straw is fully colonized by the mycelium, it will be ready to fruit and, eventually, contribute to a bountiful mushroom harvest. After harvesting, the spent substrate can be composted or utilized in a variety of ways, such as uses for spent mushroom substrate in gardens.

Preparation of Supplemented Sawdust Substrate

Supplemented Sawdust Substrate in Mushroom Grow Bag

Supplemented sawdust is a preferred choice for many commercial mushroom operations due to its ability to support a rich mushroom harvest. This substrate is particularly beneficial for varieties such as oyster, shiitake, lion's mane, and other wood-loving mushrooms like enoki and Reishi. The preparation involves a few critical steps to ensure that the substrate is sterile and rich in nutrients:

  1. Selecting and Mixing the Sawdust: Begin with fine hardwood sawdust, which is the best for wood-loving mushrooms. To this, add a nutritional supplement, commonly wheat bran or rice bran, at a ratio of 20% to the sawdust volume. This creates a nutrient-rich substrate that supports the extensive growth of mycelium.

  2. Moistening the Mix: Add water to reach a moisture content of 60-65%. Proper moisture is essential for the growth of the mycelium and should be evenly distributed throughout the sawdust. Aim for a consistency where the sawdust holds together when squeezed but does not release excess water.

  3. Packing for Sterilization: Fill the bags or jars with the moistened, supplemented sawdust, leaving space at the top for expansion and ensuring that the mixture is not packed too densely to maintain aeration. Close the bags with a breathable filter patch or use jars with a suitable closure.

  4. Sterilization Process: Sterilize the packed substrate by placing it in a pressure cooker or autoclave. The temperature must reach at least 121°C (250°F) and be maintained for 90 minutes to ensure that any contaminants are destroyed. This step is crucial as it prevents competition from other fungi or bacteria during the mushroom grow phase.

  5. Cooling the Substrate: After sterilization, it's imperative to allow the substrate to cool in a sterile environment to prevent contamination. The substrate should reach room temperature before any further handling to ensure it's safe for eventual inoculation.

By following these steps, you'll have a suitable substrate for your mushroom cultivation efforts, providing an ideal environment for the mycelium to thrive. Remember, while this article focuses on substrate preparation, the actual inoculation and fruiting are separate processes that also require careful attention to detail and sterility.

With the supplemented sawdust substrate prepared and sterilized, it is ready for the next stages of mushroom cultivation when the grower chooses to proceed.

Preparation of Supplemented Coco-Coir Substrate

Coconut Coir Substrate in Mushroom Grow Bag

Supplemented coco-coir is a widely used substrate due to its affordability, ease of preparation, and effectiveness for growing a variety of mushrooms, including Oyster Mushrooms and Psilocybe cubensis. Below is the process for preparing this substrate:

  1. Hydrating the Coco-Coir: Begin by expanding the coco-coir block by adding water. Coco-coir usually comes in a compressed form, and adding water will cause it to expand and loosen up. Use enough water to fully saturate the coir but avoid making it overly soggy. The ideal moisture content for coco-coir should allow you to squeeze water out with moderate hand pressure.

  2. Mixing in Supplements: Once hydrated, mix in supplements like vermiculite and gypsum. Vermiculite will improve the aeration and moisture retention of the substrate, while gypsum provides calcium and sulfur, essential nutrients for mushroom growth. A general guideline is to add 10% by volume of vermiculite and 2-5% of gypsum.

  3. Pasteurization: To pasteurize the supplemented coco-coir, you have several options:

    • Hot Water Bath: Submerge the mixture in hot water maintained at 60-80°C (140-175°F) for 1-2 hours. This method is suitable for small batches.

    • Oven Pasteurization: For smaller amounts, you can use an oven. Place the moist substrate in oven bags or containers and heat it at around 65-80°C (150-175°F) for about 2 hours.

    • Steam Pasteurization: For larger batches, steam pasteurization can be used by placing the substrate in a steam chamber or over a boiling water bath, covered, for 90 minutes to 2 hours.

  4. Cooling: After pasteurization, allow the substrate to cool to room temperature. This can take several hours. Avoid the temptation to rush this process, as adding mushroom spawn to a hot substrate can kill it.

  5. Draining: If any excess water is present, allow the substrate to drain properly. The substrate should be moist but not dripping water. Excessive moisture can lead to anaerobic conditions and promote the growth of unwanted bacteria and molds.

  6. Bagging the Substrate: Once cooled and drained, the substrate is ready to be bagged for use. You can use polypropylene grow bags or any other suitable container that allows for gas exchange but prevents contamination.

  7. Storage: Store the prepared substrate in a clean area while it awaits inoculation. It should be used within a short period to prevent contamination or drying out.

By following these steps, you'll have a suitable substrate for growing mushrooms that require a nutritious and moisture-retentive environment. Coco-coir, with its natural resistance to mold and bacteria, mixed with vermiculite and gypsum, makes for an excellent mushroom-growing medium.

Preparation of Spent Coffee Grounds Substrate

Coffee Grounds on Coffee Filter

Spent coffee grounds are an attractive substrate option for mushroom cultivation, particularly for varieties such as oyster and lion's mane mushrooms. They are readily available and rich in nitrogen, which is beneficial for the growth of many mushroom species. Here's how to prepare this substrate:

  1. Collecting Spent Coffee Grounds: Gather spent coffee grounds from coffee machines or local coffee shops. It's important to use them quickly after they have been brewed to avoid mold growth. If you're not using them immediately, store them in a sealed container in the refrigerator to slow down any microbial activity.

  2. Drying the Coffee Grounds: If the coffee grounds are excessively moist, spread them out on a tray to air dry, reducing the moisture content to avoid any premature decomposition or mold formation. The coffee grounds should be damp to the touch but not wet.

  3. Supplementation (Optional): While not always necessary, you can supplement the coffee grounds with a source of cellulose like sawdust or straw to create a more balanced substrate. This step can enhance the growth potential for the mycelium by providing additional nutrients and structure.

  4. Sterilization: To sterilize the coffee grounds, you can use one of the following methods:

    • Oven Sterilization: Spread the grounds on a baking sheet and place them in an oven preheated to 160-180°C (320-356°F) for about 30 minutes to an hour.

    • Pressure Cooking: For smaller quantities, you can place the grounds in jars or bags and pressure cook at 121°C (250°F) for 90 minutes. This method is highly effective at killing potential contaminants.

    • Boiling: For a low-tech option, you can boil the coffee grounds in water for at least 30 minutes. However, this method may not be as effective as pressure cooking or oven sterilization.

  5. Cooling: After sterilization, allow the coffee grounds to cool completely to room temperature in a sterile environment. This step is crucial to prevent killing any subsequently added mushroom spores or spawn.

  6. Draining Excess Moisture: If you boil the coffee grounds, ensure to drain any excess water after sterilization. The substrate should be moist but not waterlogged, as overly wet conditions can lead to bacterial growth and poor mycelium development.

  7. Bagging the Substrate: Once cooled and at the proper moisture level, the coffee grounds are ready to be bagged in suitable grow bags equipped with filter patches. These bags will maintain the necessary humidity and allow for gas exchange while keeping contaminants out.

By using these steps, you can convert a waste product into a valuable resource for mushroom cultivation. Spent coffee grounds are a viable and effective substrate that, when prepared correctly, can lead to a robust and healthy mushroom crop.

Preparation of Horse Manure Substrate

Horse Manure Substrate in Mushroom Grow Bag

Horse manure is a classic substrate for cultivating varieties like white button mushrooms, portobello, and cremini. Its rich nutrient content makes it an excellent medium for mushroom growth when properly pasteurized. The following outlines the steps to prepare horse manure for use as a mushroom substrate:

  1. Sourcing Quality Manure: Obtain fresh horse manure from stables or farms. Freshness is vital because older manure might already be composted or have a reduced nutrient profile. Ensure that the manure is free from de-wormers and other chemicals harmful to mushrooms.

  2. Pre-Composting (Optional): While not always necessary, some growers prefer to pre-compost the manure for a week or two. This process helps to break down the manure further and initiates microbial activity, which is beneficial for mushrooms.

  3. Moistening the Manure: If the manure is dry, add water to achieve a high moisture content. The manure should be wet enough to stick together but not so wet that water squeezes out when compressed. Proper moisture is crucial for successful pasteurization.

  4. Pasteurization: To pasteurize the manure, use one of the following methods:

    • Hot Water Bath: Submerge the manure in water heated to 60-80°C (140-175°F) for 1-2 hours. This method is suitable for small to medium batches.

    • Steam Pasteurization: For larger quantities, steam pasteurization is effective. Place the manure in a sealed container or chamber with steam for 1-2 hours at the same temperature range.

    • Solar Pasteurization: In hot climates, you can use solar pasteurization by placing the manure in black bags under direct sunlight for several days. This method relies heavily on environmental conditions and may not be as reliable as the others.

  5. Cooling the Manure: After pasteurization, let the manure cool to room temperature before handling. It is important not to rush this step to prevent harming the mushroom culture.

  6. Draining and Aerating: If the manure is too wet after pasteurization, allow it to drain. Aerate it by turning it over a few times to introduce oxygen, which is beneficial for the mushroom mycelium.

  7. Bagging or Spreading the Substrate: Once the manure is cool and at the right moisture level, it can either be bagged in breathable bags or spread in trays, depending on your cultivation method.

By following these steps, you will have prepared a nutrient-rich horse manure substrate suitable for growing a variety of gourmet mushrooms. Pasteurization is key in this process, as it ensures the elimination of harmful pathogens while retaining the beneficial bacteria needed to support mushroom growth.

Preparation of Cardboard Substrate

Cardboard Mushroom Substrate in Grow Bag

Cardboard is an excellent, low-cost substrate for varieties like oyster mushrooms, making it accessible for beginners or those with low tech mushroom farms. The process for preparing cardboard as a substrate is straightforward:

  1. Selecting the Right Cardboard: Use plain, untreated cardboard without glossy finishes, inks, or labels. Corrugated cardboard is preferred because its structure allows for better mycelium growth.

  2. Shredding or Breaking Down: Tear the cardboard into smaller pieces or shred it, if possible. This increases the surface area and facilitates better colonization by the mushroom mycelium.

  3. Soaking the Cardboard: Soak the cardboard pieces in water to soften them and make them more pliable. This step also helps to remove any residual substances that may inhibit mycelium growth.

  4. Pasteurization: Submerge the soaked cardboard in hot water between 60-80°C (140-175°F) for at least one hour. This temperature range is sufficient to kill off unwanted pathogens without destroying beneficial organisms. Unlike compost or manure, cardboard does not need a high degree of pasteurization due to its lower contamination risk.

  5. Draining and Cooling: After pasteurization, drain the cardboard and allow it to cool to room temperature. Ensure that it remains moist but not dripping wet, as excess water can lead to anaerobic conditions that are detrimental to mushroom growth.

  6. Layering and Inoculation: Once cooled, lay the pieces of cardboard in a container, alternating with layers of mushroom spawn. This can be done in a plastic container, a grow bag, or any other suitable cultivation vessel.

  7. Incubation: Close the container or bag loosely to maintain humidity while still allowing some air exchange. Store it in a dark and warm place, where it will remain until the mycelium fully colonizes the substrate.

  8. Monitoring: Check periodically to ensure that the cardboard does not dry out. If it appears to be getting too dry, mist it lightly with water to maintain the necessary moisture levels for mycelium growth.

Cardboard as a substrate can be particularly appealing for its simplicity and the ease with which one can obtain the materials. It's also an environmentally friendly option, as it repurposes a common waste product. This method is highly forgiving and can yield successful results without the need for specialized equipment.

Preparation of Wood Logs Substrate

Shiitake Growing From Wood Logs

Wood logs are an ideal substrate for growing mushrooms that prefer a wood-based habitat, such as shiitake, reishi, and turkey tail. The process for using wood logs involves minimal preparation but requires patience for the mycelium to colonize and produce mushrooms. Here’s how to prepare wood log substrates:

  1. Selecting Suitable Logs: Choose freshly cut hardwood logs from species like oak, maple, or beech. The logs should be cut during the dormant season (late winter to early spring) for optimal nutrient content and should be 4-8 inches in diameter and about 3-4 feet in length.

  2. Storage Before Inoculation: If you’re not inoculating immediately after cutting, store the logs in a shaded, cool place to prevent them from drying out. They should be used within a few weeks of cutting to ensure they haven’t been colonized by other fungi.

  3. Inoculation with Mushroom Spawn: Drill holes into the logs spaced about 6 inches apart in a diamond or grid pattern. Each hole should be slightly deeper than the length of the plug spawn you are using.

  4. Inserting the Spawn: Insert mushroom plug spawn into the holes. Plug spawn are small wooden dowels that have been inoculated with mushroom mycelium. Use a hammer or mallet to gently tap the plugs into the holes.

  5. Sealing the Holes: Seal the holes with a food-grade wax to protect the spawn from drying out and to keep competing organisms out. Beeswax or cheese wax works well for this purpose.

  6. Stacking the Logs: Once inoculated, stack the logs in a “log cabin” style or lean them against a support in a shady, moist area. The location should be protected from direct sunlight and wind, which can dry out the logs.

  7. Maintenance: During dry periods, water the logs to maintain moisture, which is critical for mycelium growth. However, avoid overwatering as this can lead to saturation and potential problems with mold.

  8. Waiting for Colonization: It can take anywhere from 6 months to 2 years for the mycelium to fully colonize the log, depending on the mushroom species and environmental conditions. You’ll know colonization is underway when you see the mycelium growing on the ends of the logs.

  9. Fruiting: Once fully colonized, the logs will begin to fruit naturally, usually during the spring and fall when the temperature and moisture levels are right. Some logs may require “shocking” into fruiting by soaking them in cold water for 24 hours.

  10. Harvesting: Harvest the mushrooms as they appear by gently twisting them off the logs. Be careful not to damage the underlying mycelium.

Using wood logs is a natural and sustainable method for mushroom cultivation. It's well-suited for those looking for a low-maintenance and long-term approach to growing mushrooms.

Preparation of Brown Rice Flour and Vermiculite Substrate

Brown rice Flour and Vermiculite Mushroom Subsrate

The combination of brown rice flour and vermiculite makes an excellent substrate for many types of mushrooms due to its nutrient content and water retention properties. This substrate is particularly popular among beginners and is commonly used in the production of mushroom grow kits. Here’s a detailed guide to preparing this substrate:

  1. Gathering Materials: Obtain brown rice flour, which serves as the nutrient base, and vermiculite, which acts as a water-retentive agent. Make sure the vermiculite is fine to medium grade for the best results.

  2. Mixing the Substrate: Create the substrate mix by combining 2 parts vermiculite, 1-part brown rice flour, and 1 part water. The ratios should be by volume, not weight. Mix thoroughly in a large, clean bowl to ensure even distribution of the flour and water throughout the vermiculite.

  3. Filling the Containers: Fill your sterilization containers (such as wide-mouthed half-pint mason jars) with the substrate mixture, leaving about half an inch of space at the top. Do not pack down the substrate; it should remain loose to allow for proper mycelium colonization.

  4. Sterilization: Before sealing the containers, clean the rims and cover them with a layer of dry vermiculite. This acts as a contamination barrier. Place the lids on the jars loosely to allow for pressure equalization and cover them with aluminum foil to prevent water from getting in during the sterilization process.

  5. Pressure Cooking: Place the jars in a pressure cooker and sterilize at 15 psi for 90 minutes. This high-pressure sterilization is essential to kill any potential contaminants in the substrate.

  6. Cooling Down: After sterilization, allow the jars to cool completely to room temperature within the pressure cooker or a sterile environment. This step is crucial, as adding mushroom spores or spawn to a hot substrate can kill them.

  7. Inoculation: Once cooled, the substrate is ready to be inoculated with your chosen mushroom spores or spawn. This should be done in as sterile an environment as possible to minimize the risk of contamination.

  8. Incubation: Store the inoculated jars in a dark place at an appropriate temperature for the mushroom species you are growing. The jars should remain there until the substrate is fully colonized by the mycelium, which can be identified by a white, web-like growth throughout the jar.

  9. Fruiting Conditions: After colonization, introduce the jars to fruiting conditions specific to the mushroom species being cultivated. This often involves exposing them to higher humidity, fresh air exchange, and sometimes light.

By following these steps, even those new to mushroom cultivation can create a suitable environment for growing a variety of mushrooms. This substrate is especially effective for small-scale cultivation and provides a forgiving medium for mushroom development.

Preparation of Grain-Based Substrates for Mushroom Cultivation

Grain-based substrates, such as rye berries, wild bird seed, and red milo sorghum, are popular choices for creating mushroom spawn due to their excellent nutrient content and water retention capabilities. Below are detailed procedures for preparing each of these grain-based substrates.

Creating the perfect grain spawn can be a meticulous process. If you'd rather skip straight to cultivation, consider our sterilized grain spawn, which is ready for inoculation with your choice of mushroom spores.

Part of the mushroom cultivation adventure is experimenting with inoculation techniques. Our liquid cultures offer a convenient and reliable starting point for your experiments.

Preparation of Rye Berries for Mushroom Cultivation

Rye Berry Mushroom Substrate in Grow Bag

  1. Rinsing and Soaking: Begin by thoroughly rinsing the rye berries to remove any dust or debris. After rinsing, soak the grains in water for 12-24 hours. This soaking process helps to hydrate the berries and initiate germination, which can reduce the risk of contamination.

  2. Boiling: Drain the soaked rye berries and then boil them for 10-15 minutes until they are slightly soft but still intact. Overcooking can cause burst berries, which can lead to clumping and increase the risk of contamination.

  3. Draining and Drying: After boiling, drain the rye berries and allow them to dry so that they are not overly wet. They should be moist without any excess water, as too much moisture can lead to bacterial growth.

  4. Jar Filling: Fill your jars with the prepared rye berries, leaving sufficient space at the top. Fit with a filter disk or a synthetic filter material to allow for gas exchange while preventing contamination.

  5. Sterilization: Sterilize the jars in a pressure cooker at 15 psi for 90 minutes to ensure that all potential contaminants are destroyed.

  6. Cooling: Allow the jars to cool to room temperature in a sterile environment to prevent condensation from forming inside the jars.

Preparation of Wild Bird Seed for Mushroom Cultivation

Wild Bird Seed Mushroom Substrate in Grow Bag

  1. Cleaning: Rinse the wild bird seed thoroughly to remove dust and any other particulates. Some bird seed mixes may also contain oils or other additives that should be rinsed off.

  2. Soaking: Soak the bird seed in water for 12-24 hours, which hydrates the seeds and can help to leach out any anti-fungal agents that might be present.

  3. Boiling: Boil the soaked bird seed for 10-15 minutes, and then drain. As with rye berries, avoid overcooking to prevent the seeds from bursting.

  4. Drying: Spread the boiled bird seed out to dry to the point where it's no longer visibly wet, but still retains internal moisture.

  5. Jar Filling and Sterilization: Follow the same jar filling and sterilization process as for rye berries.

Preparation of Red Milo Sorghum for Mushroom Cultivation

Red Milo Mushroom Substrate in Grow Bag

  1. Rinsing and Soaking: Rinse the red milo sorghum grains under running water. Then, soak the grains for 12-24 hours to hydrate and activate germination.

  2. Boiling: Drain the soaked grains and boil them for 10 minutes. Ensure the grains remain whole and are not overcooked.

  3. Draining and Drying: Allow the grains to drain and dry sufficiently so that they are not clumping together but retain moisture.

  4. Jar Filling and Sterilization: Fill your jars with the prepared grains, leaving adequate headspace, and sterilize in a pressure cooker at 15 psi for 90 minutes.

After sterilization and cooling, all these grains are ready to be inoculated with your chosen mushroom spores or culture to create spawn. Once inoculated and fully colonized, the grain spawn can be used to inoculate larger quantities of bulk substrate for mushroom production.

Each of these grains offers different nutritional profiles and physical properties, providing options for cultivators to match the specific needs of the mushroom species they intend to grow.

Here's a table summarizing the substrates and the mushrooms that grow on them:



Suitable Mushroom Species

Pasteurized Straw


Oyster, Shiitake, Lion's Mane, Beech

Supplemented Sawdust


Oyster, Shiitake, Lion's Mane, Enoki, Reishi, and more

Supplemented Coco-Coir


Oyster, Psilocybe cubensis

Spent Coffee Grounds


Oyster, Shiitake, Lion's Mane

Horse Manure


White Button, Portobello, Cremini




Wood Logs

No prep

Shiitake, Reishi, Turkey Tail, Wood Ear

Brown Rice Flour & Vermiculite


Oyster, Shiitake, Lions Mane, Psilocybe cubensis

Coconut Coir


Oyster, Psilocybe cubensis

Rye Berries


Any mushroom type

Wild Bird Seed


Any mushroom type

Red Milo Sorghum


Any mushroom type

Substrate Specificity for Mushroom Varieties

Understanding the specificity of substrates for various mushroom species is critical in cultivation. Each species of mushroom has evolved to grow in particular conditions and substrates found in their natural environments. As cultivators, replicating these conditions as closely as possible can significantly impact the growth rate and yield of the mushrooms. By matching different types of substrates to the needs of different mushroom species, cultivators can optimize their growth cycles and maximize their harvests.

The choice of substrate is not merely a matter of what the mycelium will grow on but what it will thrive on. For example, some mushrooms, like the oyster mushroom, are aggressive colonizers and can grow on a variety of substrates, while others, like the shiitake mushroom, prefer a more specific woody substrate to produce the best results.


Choosing the right mushroom culture is crucial for success. Our collection of mushroom cultures provides a variety of options to suit your specific cultivation needs 

The following table provides an overview of substrate compatibility with various mushrooms, including typical yield and growth rate considerations:

Mushroom Species

Preferred Substrate(s)

Typical Yield

Growth Rate

Agaricus bisporus (Button, Cremini, Portobello)

Composted manure, Straw



Pleurotus ostreatus (Oyster mushrooms)

Straw, Sawdust, Coffee Grounds, Cardboard

Very High


Lentinula edodes (Shiitake mushrooms)

Hardwood logs, Supplemented Sawdust



Ganoderma lucidum (Reishi mushrooms)

Supplemented Sawdust, Hardwood logs



Hericium erinaceus (Lion's mane mushrooms)

Supplemented Sawdust, Straw



Grifola frondosa (Maitake mushrooms)

Supplemented Sawdust, Hardwood logs



Trametes versicolor (Turkey tail mushrooms)

Wood Logs, Supplemented Sawdust



Flammulina velutipes (Enoki mushrooms)

Supplemented Sawdust, Wood Logs



Hypsizygus tessellatus (Beech mushrooms)

Supplemented Sawdust, Wood Logs



Stropharia rugosoannulata (Wine cap mushrooms)

Straw, Wood Chips, Compost



Auricularia auricula-judae (Wood ear mushrooms)

Supplemented Sawdust, Wood Logs



Cordyceps militaris

Rice, Grains, Supplemented Sawdust with Additional Nutrients


Very Slow

Different Mushrooms Need Different Nutrients

For example, Agaricus bisporus, which encompasses button, cremini, and portobello mushrooms, prefers a nutrient-rich composted manure or straw substrate. This combination often results in a high yield due to the dense nutrients present in the substrate.

In contrast, Pleurotus ostreatus, commonly known as oyster mushrooms, is highly versatile and can be grown on numerous substrates. However, they particularly excel on straw, which can lead to very high yields and a rapid growth rate.

Follow Procedures for Success

When preparing substrates, it is important to follow the correct procedures, such as pasteurizing or sterilizing the material, to ensure the substrate is conducive to mushroom growth and free from contaminants. For instance, boiling a substrate doesn’t get it hot enough for sterilization but may suffice for pasteurization, depending on the material.

The use of spent substrate is also a consideration for cultivators. After the mushrooms have been harvested, the amount of spent substrate can be significant. However, this material can often be reused or recycled, such as by adding it to compost piles, where it can remain in the substrate mix and contribute to soil fertility.

Whether a substrate is used as a primary material for mushroom growth or as a supplement for bulk grows, its preparation and maintenance are vital. Cultivators must ensure substrates like grains are not overcooked to the point of bursting, which can lead to piles of spent substrate that are unusable. Properly inoculated with mushroom spores, these substrates can become effective substrates for growing a wide array of mushrooms.

The selection of the right substrate, along with the knowledge of how to dispose of the used substrate responsibly, contributes to an inexpensive and effective substrate strategy for both hobbyists and commercial growers. By understanding the substrate materials that could be ideal for specific mushrooms, cultivators can create an optimized environment that makes for an excellent mushroom cultivation experience.

Conclusion: Fostering Growth Beyond the Substrate

As we reach the culmination of our exploration into the world of mushroom substrates, it's clear that the foundation of successful cultivation lies in understanding and selecting the right medium. From the nutrient-dense compost that nourishes the robust growth of Agaricus bisporus to the versatile straw that bolsters prolific Pleurotus ostreatus harvests, each choice in substrate is a step towards a fruitful yield. The nuances of sterilization and pasteurization, along with the conscientious reuse or disposal of spent substrates, reflect meticulous care and respect for both the craft and the environment.

The journey of a mushroom cultivator is one of constant learning and adaptation. Personal experimentation within the parameters of scientific understanding can lead to innovative approaches and perhaps, even more importantly, to personal growth and a deeper connection with the natural world. As such, we encourage readers not only to apply the insights gained from this article but also to become part of the broader community of mushroom enthusiasts. By engaging with fellow cultivators, sharing experiences, and exchanging knowledge, we can all contribute to the collective wisdom that enriches this fascinating field.

In the spirit of fostering a sense of connection and ongoing learning, we urge you to reach out to local mycology clubs, participate in online forums, and attend workshops. Remember, every expert was once a beginner, and the shared experiences within the community can be as nurturing as the substrates we prepare for our mushrooms.

Mushroom Supplies List:

Whether you're a seasoned cultivator or just beginning your mushroom journey, having the right supplies on hand is essential. Here's where you can find everything you need:


Frequently Asked Questions:

Q: What is the purpose of mushroom substrates?

A: Mushroom substrates serve as the growing medium for mushrooms. It provides the necessary nutrients and environment for the mushrooms to thrive.

Q: What are the common mushroom substrates used?

A: Common mushroom substrates include straw, wood chips, sawdust, coffee grounds, and compost. These materials can be used alone or in combination to create an ideal growing medium.

Q: How do I choose the best mushroom substrate?

A: The best mushroom substrate depends on the type of mushroom you are growing. Different species of mushrooms have different preferences in terms of substrate materials. Researching the specific requirements of the mushroom species you are cultivating will help you choose the most suitable substrate.

Q: Do I need to sterilize my substrate before using it?

A: Yes, it is recommended to sterilize your substrate to eliminate any potential contaminants that may hinder mushroom growth. This can be done through methods such as boiling or heating the substrate to temperatures that kill off unwanted organisms.

Q: Can spent mushroom substrate be re-used?

A: Spent mushroom substrate can be utilized in several ways. While it may not be suitable for growing another round of mushrooms, it can be used as a soil amendment in gardening or composting.

Q: How can I supplement my mushroom substrate?

A: Supplementing your mushroom substrate involves adding additional nutrients or materials to enhance its nutritional value. This can be done by adding supplements such as bran, gypsum, or other organic materials.

Q: What is the role of water in the substrate?

A: Water is essential in mushroom cultivation as it provides the necessary moisture for mushroom growth. The substrate should be kept moist but not overly saturated.

Q: What are some uses for spent mushroom substrate?

A: Spent mushroom substrate can be used as a soil conditioner, compost ingredient, or even as a growing medium for other plants. It contains beneficial nutrients that can enrich the soil and support plant growth.

Q: Can different substrate materials be mixed?

A: Yes, different substrate materials can be mixed to create a suitable substrate for growing mushrooms. Experimenting with different combinations can help you find the best substrate recipe for the mushroom species you are cultivating.

Q: How much spent mushroom substrate do I need?

A: The amount of spent mushroom substrate you need depends on the scale of your cultivation. It is recommended to have enough substrate to create a layer at least a few inches thick in your growing containers.