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  • Writer's pictureBart Acres

Glossary of Common Mushroom Cultivation Terms

Updated: Apr 24, 2023

When reading material in books or online about mushroom cultivation, you may come across words and terms you’re not familiar with. Here is a list of some of the lingo that you will encounter and explantions of what they mean.

Abort When a mushroom has begun to form but terminates prior to reaching maturity. ‘Aborts’ can happen for several reasons, most commonly this is due to inadequate growing conditions (e.g. too dry, too wet, too cold, too hot, too windy) but can also happen naturally if the intial pinset has too many mushrooms for the organism to support, it will ‘abort’ a few and focus on growing a lesser number of decent sized mushrooms.

Agar Plates Petri dishes which contain a nutritive agar gel that enables mushroom cultures to be grown on them. Mycelium spreads across the surface of the agar and can be cut out with a scalpel and introduced into other substrates. Agar plates are used as a way to purify (clean up contamination), propagate, and store mushroom cultures.

Block A ‘block’ shaped bag of mycelium growing on sawdust based substrate held inside a filter patch bag. A common way of growing and fruiting many species of gourmet mushrooms.

Casing Layer a layer of non-nuritive but moisture retentive material spread on the top of the fruiting surface for cultivation of some species of mushrooms (such as button mushrooms). Usually used for mushrooms that naturally grow off of the ground (rather than on logs). It protects the substrate and holds moisture while providing a good environment for the initial stages of fruitbody formation.

CO2 Carbon dioxide is a biproduct of the mushrooms metabolism. If mushrooms are fruited in too much of an enclosed space, the CO2 that they ‘exhale’ can accumulate and cause spindly, elongated fruitbodies (See FAE / Fresh Air Exchange)

Colonisation The process of mycelium growing through a substrate. When this is completed the substrate is said to be ‘fully colonised’

Contamination Unwanted organisms like mold or bacteria growing in your growing medium

Culture A pure isolated strain of a species of mushroom which is used to inoculate substrates. Mushroom cultures are stored on agar plates and then turned into whatever kind of spawn is needed for the intended method of cultivation (e.g. dowels for making logs or grain spawn for inocluating loose substrates)

Dowel spawn / mushroom dowels Small wooden columns which have mycelium growing on and in them, to use for inoculating mushroom grow logs

Flush A crop of mushrooms. Grow kits, logs and outdoor patches will typically have multiple flushes over a period of time, if kept healthy and well looked after.

Fresh Air Exchange (FAE) The amount of oxygen rich fresh air that fruiting mushrooms recieve. This is to expel the CO2 that the mushrooms produce and provide them with fresh air. The answer to many mushroom growing questions if it pertains to weird looking or elongated / spindly fruitbodies, is ‘needs more FAE!’

Fungus gnat A small fly that lays its larvae in mycelium and mushroom stems. The main enemy of the mushroom grower!

Gills the frilly linear structures under a mushroom cap which release spores. Some mushrooms have pores or teeth instead of gills.

Grain spawn Hydrated and sterilised whole grains colonised with mycelium used to inoculate substrates

HEPA flow hood / Laminar Flow Hood An air filter which blows sterile air over a workspace. HEPA stands for ‘High Efficiency Particulate Air’ filter

Hyphae Tiny microscopic strands of mycelium

Hyphal knot The first stage of growth of mushrooms

Incubate Providing the right conditions for mycelium to colonise a substrate. Darkness, right temperature, high humidity

Inoculate The process of introducing a mushroom culture to a prepared substrate. Usually achieved with grain spawn or dowel spawn

Liquid culture Pure mycelium suspended in sterile nutrient broth. Usually contained in a syringe, for injecting onto sterile grain to make spawn.

Misting Using a mister bottle to spray a fine mist of water into a mushroom growing environment to provide humidity. Mist can also be provided by mechanised means for larger scale or more high tech grow spaces, such as ultrasonic humidifiers or high pressure mist nozzle sprayers.

Morphology The observable physical charachteristics of a mushroom, e.g. its shape, colour, size, which can be determined by both its genetics and the environmental conditions which it is grown in.

Mycelium The living ‘body’ of the mushroom organism. Visible as white fuzz or strands on and inside the substrate

Mycology The scientific study of mushrooms and fungi

Mycorrhizal Fungi which live in association with the roots of living plants and trees. Generally, mycorrhizal fungi are considered mutually beneficial for both the plant and the fungus with each providing something of value to the other.

Pasteurisation The process of killing off unwanted spores and organisms in a substrate using heat or pH changes

Perlite A form of organic puffed volcanic ash which comes in varying sizes / grades. A light and inert material which has a high surface area. Commonly used to provide humidity to small grow spaces by putting some damp perlite in the area and it evaporates humidity. Can also be used as an additive to subsrates to lighten and aerate them, or as an ingredient in a casing layer.

pH the acidity or alkalinity of any given material (such as a substrate). Measured on a scale from 0 to 14 with low numbers being very acidic, high numbers being very alkaline and pH 7 is neutral pH. Lime pasteurisation creates a high pH (alkaline) of around 11 which inhibits growth of mould but does not affect growth of live mycelium such as oyster mushroom mycelium on straw.

Phenotype The observable physical traits of a mushroom or other organism as determined by its genetics (genotype)

Primordia / Pins Baby mushrooms. The next stage after hyphal knot

Rhizomorphic Vigorous healthy mycelium growth of certain species, visible as ropey white strands that rapidly spread across substrate.

Shotgun Fruiting Chamber (SGFC) A very basic, affordable, low-tek chamber for fruiting mushrooms at home. Essentially a large (60 to 120L+) plastic storage tote bin, with many holes drilled in the walls to provide adequate air exchange. Fruiting blocks are placed inside the SGFC and it is misted each day, or humidity can be provided by damp perlite which evaporates humid air into the grow space throughout the day. The name ‘shotgun’ comes from the fact that the container looks as though it’s been shot with pellets (lots of small holes).

Spawn Mycelium culture ready for use, usually in grain or dowel form.

Spore The ‘seed’ of the mushroom. Floats out of gills then germinates into mycelium when conditions are right.

Spore print Spores deposited onto a sanitary surface like tin foil, to be used for ID of wild mushrooms (based on spore colour) or to collect the spores for culturing and cultivation.

Sterilisation A more thourough version of pasteurisation. Uses high heat for prolonged periods of time (e.g in a pressure cooker) to kill off all life in the substrate, readying it for inoculation with your desired mushroom culture.

Still Air Box (SAB) A basic sterile workspace made from a large storage tote with arm holes cut in the side. The inside of the box is wiped with alcohol before working inside for sterile work like agar or grain inoculation.

Substrate The material that the mushrooms grow on. Straw, wood, grains, sawdust etc. The mycelium digests the substrate to gain access to enough nutrients and moisture to produce fruitbodies (mushrooms)

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