Mycelium, agar, colonization… what does it all mean?
Here’s a quick primer on some of the most common terms used in mushroom cultivation.
Agar: A seaweed derived powder used to make a nutrified media for petri dishes and master culture slants.
Autoclave: A vessel or pot that can be pressurized with steam. Used for sterilizing grain, substrates and agar.
Biological Efficiency: A measurement of yield. A ratio of the amount of fresh mushrooms you harvest to the weight of the wet substrate.
Block (fruiting): A term referring to the cube shape of the supplemented sawdust once it has been grown through by the mycelium. The fruiting block is usually tenacious and holds together easily.
Casing: A layer of non-nutritious material placed on top of the fruiting block or mushroom bed in order to retain moisture. Some types of mushrooms need a biologically active casing layer in order to produce fruit.
Colonization: The process of mycelium growing through a substrate, grain jar or agar filled petri dish. Once the medium is completely grown through by the mycelium it is said to be fully colonized.
Contamination: Anything living on you mushrooms, fruiting blocks or agar plates that is not supposed to be there. Contamination is typically bacteria or another type of unwanted fungus.
Culture: A living piece of mushroom mycelium. Contains all the living matter and DNA needed to produce mushroom fruitbodies.
Fruitbody: The edible part of the mushroom, or what people typically consider “mushrooms.”
Fruiting: The event of mushroom structure or fruitbodies emerging from the substrate.
Gypsum: Calcium Sulfate. Used often in substrates as an acidifier, or in grain spawn to prevent the individual grain kernels from clumping together.
G2G: Shorthand for Grain to Grain transfer. The process of transferring grain spawn from a fully colonized jar to fresh sterilized jar for the purpose of exponential mycelial expansion.
Inoculation: The process of adding a living piece of mushroom culture to a grain jar, or adding grain spawn to a bulk substrate.
Laminar Flow: Fluid flow that is non turbulent, ie. smooth and consistent. Needed for flow cabinets. Turbulent flow will be erratic and can suck contaminants into your work stream.
Micron: 1 millionth of a meter. Very small. Used for measuring the effectiveness of filter patches or filter sizes when deciding on a HEPA filter for your laminar flow cabinet.
Pasteurization: The process of heat treating a substrate between 65 and 82 deg C in order to kill many and delay most of the contaminants allowing your mushroom culture to take over a substrate first. Steam or hot water is usually used.
PC: Shorthand for pressure cooker, a stovetop tool used for pressure sterilization of grain spawn or substrates.
Senescence: The state where the mycelium overreaches its potential exponential growth and loses vigor. Exponentially expanding mushroom culture past this point will weaken it, leading to poor fruiting and easier contamination.
SGFC: Shot gun fruiting chamber. A tote with holes drilled on all six sides, with the bottom covered in perlite that has been soaked in water. A growing chamber for small scale mushroom cultivation.
Spawn: Any material that is overtaken by mycelium with the intention of inoculating a substrate. The most common spawn type is Rye Grain, but sawdust, millet and sorghum are also used.
Spores: The “seeds” of the mushroom. Spores usually contain half of the genetic material required for the mycelium to start growing.
Sterilization: A process which kills all living organisms from a substrate or spawn. Usually done by heating the material with steam under pressure so that the temperature can reach 121 deg C for a defined period of time.
Substrate: A medium for mycelial growth. Can be straw, sawdust, coco coir, manure, waste paper etc.
Wedge: A piece of a mushroom culture cut from a petri dish. Used for making transfers to grain jars or to transfer between plates