Welcome to our mushroom lexicon! Whether you are just starting out with mushroom cultivation or are already an advanced grower – here you will find clear explanations of the most important technical terms in modern mushroom cultivation. At Meisterpilze in Erlangen, we know that the right terminology and an understanding of fundamental concepts are crucial for your success in mushroom growing. Our high-quality selection of substrates, grain spawn products, liquid cultures, and professional accessories is based on years of experience with these processes. Let us explore the world of mushroom cultivation together.
ℹ️ Note: The English terms in parentheses (e.g., "Grain Spawn," "Liquid Culture") have been added as international search and industry terms. A standalone English version of this lexicon can be found on the English language version of the site.
Mycelium
The mycelium is the vegetative thread network of a fungus and is the actual fungal organism. It consists of fine, thread-like structures called hyphae, which spread through the substrate and absorb nutrients. The mycelium is – comparable to a vegetative supply or root network – the nutrient-absorbing organism and is responsible for the mushroom being able to bear fruit in the first place. When the mycelium grows healthily and quickly and has completely permeated the substrate, it provides the best foundation for bountiful harvests and high-quality fruiting bodies.
Grain Spawn
Grain spawn is sterilized grain – usually rye, oats, or millet – that has been inoculated with the mycelium of the desired mushroom. It serves as a starter culture and is the classic means for rapidly colonizing larger quantities of substrate. The grain provides the mycelium with optimal nutrients and enables rapid colonization, as the grains offer a large surface area and the mycelium can easily travel from grain to grain. At Meisterpilze, you will find high-quality grain spawn for all common edible mushroom species that is ready for immediate use.
Liquid Culture
Liquid culture is a sterile nutrient solution in which mycelium is cultivated instead of growing on a solid substrate. This form of culture allows for the rapid and efficient propagation of mycelium, as the fungal network can absorb nutrients from anywhere in the liquid medium, thereby promoting optimal growth. Compared to grain spawn production, liquid cultures require less space and time, making them particularly attractive for professional growers.
Injection Port
The injection port is a membrane-equipped opening in substrate containers, grow bags, or liquid culture vials, through which you can inject mycelium or spores cleanly and sterilely. The membrane self-seals after the penetration of a sterile injection needle, thus preventing the entry of contaminants. The injection port is a key innovation in modern mushroom cultivation, as it allows even beginners to perform safe and reliable injections without special equipment.
Agar / Nutrient Agar
Agar is a gelatinous gelling agent derived from red algae and used as a base for solid nutrient media. With various additives such as potato starch, dextrose, and mushroom extract, an optimal nutrient medium is created on which mycelium and spores can be cultivated. Agar plates are frequently used for isolating pure mycelium strains, storing cultures, and performing isolations. The medium is transparent, making it easy to observe mycelium growth and detect contamination at an early stage.
Petri Dish
The Petri dish (also known as a culture plate) is a flat, round dish made of plastic or glass that is filled with nutrient agar. It is the standard labware for all work with agar media and the tool of choice for small-scale, detailed cultivation work. In Petri dishes, you can isolate individual mycelium colonies, compare different strains, and build up pure cultures.
Fruiting Chamber
The fruiting chamber is a specialized, controlled room or container where conditions are set to be optimal for fruiting – i.e., the growing of the mushrooms. These conditions include the right temperature (usually between 15–22 °C depending on the mushroom species), the correct humidity (80–95 %), sufficient light, and regular air exchange. Many growers build their own fruiting chambers out of plastic boxes, shelving, or more professional constructions – a well-equipped fruiting chamber is the key to consistent, high-quality harvests.
Spore Print
The spore print is a simple method for collecting and storing the spores of a mature fruiting body. To do this, place a mushroom cap on a piece of paper, agar, or foil for several hours to overnight – the tiny spores then fall like fine dust onto the surface and create an impression of the gill system. These spores can later be used to cultivate new cultures; they have a long shelf life.
⚠️ Safety Warning – Mushroom Spores (Respiratory Tract): When making a spore print, fine spores are released. Avoid inhalation, work in a well-ventilated room, and wear a respiratory mask (FFP2/FFP3) if you are sensitive, allergic, or have pre-existing conditions, as well as if performing the task frequently. Mushroom spores can irritate the respiratory tract and trigger allergic reactions. For details, see the safety warning at the end of this page.
Contamination
Contamination refers to the unwanted colonization of your mushroom cultures by foreign microorganisms such as bacteria, mold spores, or other mushroom species. Contamination spoils your substrate, can lead to poor harvests, and spreads rapidly if it goes unnoticed. Visible contamination often appears as green, black, orange, or otherwise discolored spots in the substrate. The best strategy against contamination is prevention through clean work methods, sterile tools, and adherence to hygiene protocols – which is why at Meisterpilze, we place great importance on high-quality sterilized raw materials.
Sterilization vs. Pasteurization
Sterilization is a process in which all microorganisms (including spores) are killed in a material, usually through steam pressure in an autoclave or via pressure and heat. Pasteurization, on the other hand, uses milder heat (often 60–80 °C) over a longer period and destroys only most, but not all, heat-resistant microorganisms. Sterilization is the safer procedure for sensitive work such as liquid cultures and agar, while pasteurization is sufficient for more robust substrates like straw compost and consumes less energy.
⚠️ Safety Warning – Steam Pressure/Autoclave: Sterilizing under steam pressure (approx. 121–130 °C) creates significant risks of scalding and pressure-related hazards. Use only intended, pressure-tested equipment, follow manufacturer instructions and pressure release guidelines, never open the container under pressure, and allow it to cool completely before opening. See also the entry "Autoclave."
CVG (Coco, Vermiculite, Gypsum)
CVG is a commonly used substrate mixture consisting of coco coir (for water retention), vermiculite (for aeration and water retention), and gypsum (for structure). This mixture offers excellent properties for many different gourmet and wood-loving mushroom species – it is loose, water-retaining, and airy all at once. CVG is low-nutrient and relatively contamination-resistant, relatively inexpensive to produce, easy to sterilize, and enables consistent, reliable harvests.
Master's Mix
Master's Mix is another popular substrate mixture, but unlike CVG, it is a nutrient-rich wood substrate: it typically consists of hardwood sawdust and soybean hulls (or wheat bran) – often in a ratio of about 1:1 – occasionally supplemented with gypsum. Because it is nutrient-rich, Master's Mix must be sterilized. It is primarily suitable for wood-loving gourmet mushrooms (e.g., oyster mushrooms, lion's mane). For such species, a supplemented wood substrate can yield higher harvests than a pure, hydrating base substrate like CVG. (Not to be confused with CVG made of coco coir, vermiculite, and gypsum.)
Substrate
The substrate is the growth medium in which your mushroom thrives – essentially the nutrient medium in solid form. It can consist of a wide variety of materials: mushroom compost, straw compost, wood fibers, sawdust with additives, coco coir mixtures, or special blends like CVG. The substrate provides the mycelium with nutrients, water, and structure. Choosing the right substrate is crucial for success – different mushroom species prefer different substrates, and a high-quality substrate can make the difference between average and excellent harvests.
All-in-One Growbag
The All-in-One Growbag is a prepared, sterile plastic bag that is already equipped with sterilized substrate, an injection port for mushroom inoculation, and often a special filter patch for air exchange. You simply need to inject your grain spawn or liquid culture through the injection port, and the rest happens on its own – the mycelium colonizes the substrate, and after a few weeks, you receive your first harvest. All-in-One Growbags are ideal for beginners, as they minimize the risk of contamination and enable professional results even without special equipment.
Grain to Grain Transfer (G2G)
Grain to Grain Transfer means transferring grain spawn from one culture to new grain in order to propagate the culture without using liquid cultures or agar plates. This is a fast and simple method for producing grain spawn in larger quantities – you simply divide the colonized grain spawn and distribute it onto sterile grain. G2G is faster than propagation via agar and costs less in materials, but is primarily suitable for experienced growers, as the risk of contamination is higher.
Break and Shake
Break and Shake is a technique where you carefully break up and shake the grain spawn bags during the colonization process after the mycelium has colonized about 15–25 % of the grain. This distributes the mycelium more evenly throughout the bag and significantly accelerates further colonization – instead of several weeks, colonization can be completed in 1–2 weeks.
Pinning / Primordia
Pinning refers to the appearance of the very first tiny mushroom buds (primordia) on the substrate surface – these look like small pins, hence the name. This is the most exciting moment for every grower, as it shows that the fruiting conditions are correct and the mushroom will soon bear fruit. Primordia are extremely small, white or slightly discolored dots that quickly grow into visible mushrooms.
Flush
A flush is a cohesive harvest period in which multiple mushrooms fructify simultaneously or close together in time and become ready for harvest. After the first harvest, the substrate often enters a resting phase – after which a second, third, or even fourth flush can occur, depending on the mushroom species and substrate quality. Flushes usually become somewhat weaker with each round, but many growers report that they can obtain a total of 2–4 good flushes from one substrate.
Dunking
Dunking means completely submerging the substrate in water for 12–24 hours after a harvest (or between two flushes). This rehydrates the substrate and gives the mycelium the energy to produce the next wave of mushrooms. Dunking is particularly effective between flushes and can significantly improve the quantity and quality of subsequent harvests.
FAE (Fresh Air Exchange)
FAE (Fresh Air Exchange) means regular air exchange – the removal of stale, carbon dioxide-enriched air and the introduction of fresh outside air. Mushrooms need oxygen to grow, and without sufficient FAE, deformities, slow growth, or even a total lack of fruiting can occur. In professional fruiting chambers, FAE is achieved through small ventilation openings, fans, or filter combinations.
Monotub
A Monotub is a simplified DIY fruiting system, often consisting of a large plastic container that is filled with mushroom substrate and prepared in such a way that it creates optimal fruiting conditions. The lid is fitted with small holes to allow for FAE, and moisture-retaining material is added. Monotubs are cost-effective, effective, and popular among hobby growers who want to build their own first fruiting chamber.
Laminar Flow Hood
A Laminar Flow Hood is a specialized device that blows filtered, sterile air at a constant speed over a workspace, thereby creating a germ-free working environment. This is the professional tool for high-precision work such as agar plate work, isolations, or liquid culture production. A Laminar Flow Hood significantly reduces the contamination rate and enables faster, more reliable work.
Autoclave
An autoclave is a large, sealed stainless steel pot with a pressure mechanism in which materials are sterilized using high-pressure steam – this is the gold standard for complete sterilization. The autoclave generates temperatures of approximately 121–130 °C under pressure and reliably kills even heat-resistant spores if held for a sufficient duration. Autoclaves are indispensable for the professional production of substrates, grain spawn products, and nutrient media.
⚠️ Safety Warning – Pressure Vessel/Scalding: An autoclave operates with hot steam under pressure. Use only pressure-tested equipment, always observe manufacturer instructions, let the pressure out in a controlled manner, never open the autoclave under pressure, and allow it to cool completely before opening. There are risks of scalding and pressure-related hazards.
We hope this mushroom lexicon helps you better understand the technical terms and concepts surrounding mushroom cultivation. At Meisterpilze in Erlangen, we offer all the materials and products you need for successful mushroom cultivation – from high-quality substrates to professional accessories.
What you need for it:
- Grain spawn for all common edible mushroom species
- CVG and Master’s Mix substrates
- All-in-One Grow Bags for an easy start
- Liquid cultures & Petri dishes for your own cultures
- Sterile materials & filter bags
ℹ️ Note – Fresh Mushrooms: Fresh mushrooms are available on Saturdays at the Erlangen weekly market or via "Marktschwärmer" – not in our online shop. In the shop, you will find everything for your own mushroom cultivation.
⚠️ Safety Warning – Mushroom Spores (Respiratory Tract)
Mature mushrooms release spores. Inhaling large quantities of spores can irritate the respiratory tract and lungs and, with repeated exposure, trigger allergic reactions such as extrinsic allergic alveolitis ("Mushroom Worker’s Lung").
- Allow fruiting in well-ventilated rooms; do not place in bedrooms or living areas.
- Harvest mushrooms just before they release their spores to reduce the spore load.
- Sensitive, allergic, or pre-existing condition sufferers, as well as those with continuous exposure: wear respiratory protection (FFP2/FFP3).
- Never consume contaminated or moldy cultures; dispose of the bag closed, ensuring spores are not stirred up or inhaled.