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A Guide to Cultivating Mushroom Spawn

Mushroom Spawn: any substance that has been inoculated with fungus mycelium to promote growth of the vegetative stage of fungi life cycle.

Scientists, farmers, hobbyists, and people of all walks of life are exploring the realms of fungi cultivation. Whether for research, food production, or basic interest in the field, the most important aspect of producing your own fungi is maintaining clean spawn.

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Some Reasons to Cultivate Fungi!Humanity has always shared a strong tie with fungi, whether producing alcoholic beverages, consumption in diets, uses in medicines, or guides to spiritual enlightenment. Regardless of reasoning, the art of mushroom cultivation is a satisfying adventure for beginners and veterans alike. Here are a few examples of fields of interest in mushroom cultivation:

Culture/Health Benefits The Chinese culture has always revered the Ling Zhi mushroom

(Ganoderma lucidum) for its good luck traits in supporting life and longevity; modern science has gone on to assure the benefits of Reishi consumption in cancer treatments, diabetes prevention, and neuroprotection relating to dopamine levels in the brain [1,2,3].

Beauty The turkey tail mushroom (Trametes versicolor), admired by

mycophiles for its beautiful appearance, exhibits anti-cancerous traits by the simple consumption of the raw fruiting body [4].

Diet The all-common oyster mushroom (Pleurotus ostreatus) is enjoyed

worldwide for its delectable taste, and ease in cultivation. Modern science is currently investigating health benefits of complex polysaccharide chains present in fruiting bodies [5].

Top left: rare Pink Oyster mushroom fruiting on tree trunk (http://mycosource.com/wp-content/uploads/2012/08/Pink-Oyster.jpg)Top Right: Exquisite Ganoderma lucidum flashing colors (http://www.npnutra.com/assets/images/reishi-mushroom-2.jpg)Bottom left: Turkey Tail mushroom fruiting on tree trunk (http://i.ytimg.com/vi/UN9RcvrUw64/hqdefault.jpg)

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What is mushroom spawn and why is it so essential to growing

mushrooms?

fresh substrate.

To achieve this vegetative growth, spawn substrate is most commonly grown on sawdust, or grain depending on the type of fungi being cultivated. For example, lion’s mane (Hericium erinaceus) prefers an oak sawdust substrate, compared to oyster

growth ready inoculate more

Similar to plants, fungi must first establish a vegetative body to prepare for fruiting. Fungi achieve this by producing mycelium (pictured on the bottom right); mycelium is an interconnected, branching, web-like network of cells that grow in the soil or over a substrate. Substrates are the growing medium that mycelium colonize and enzymatically break down for access to simple sugars that spur growth. In growing out this young mycelium, and letting it grow/colonize over substrate lays the essence of mushroom spawn. After colonization of substrate, the mycelium will have established vegetative

First things First: Use clean culture or isolate from fungus sample

1. Utilizing a mycelial culture already in a test tube or petri dish, using a sterile tool, transfer a small amount of mycelium (white biomass in the picture above) to a new petri dish.

2. Wrap edges of Petri dish with Parafilm to seal the microenvironment.

3. Allow enough time to for the fungi to colonize the whole dish. (1-2 weeks)

4. Watch for contamination that often manifests in an abstract color, fast growth rate, or shiny texture.

As pictured above, the petri plate of “Po Wellington P:6” is sterile culture indicated by uniform white mycelium. If your culture does contaminate, one must re-transfer into a new plate. Contamination this early in the process will certainly wreak havoc further down the line of transferring your mycelium to different media. Once your culture is colonized and clean, it is time to

After colonization of spawn substrate is completed, the transfer to the fruiting substrate is necessary.

Upon complete colonization of a spawn substrate, the spawn is transferred to fruiting substrates. When a transfer of mycelium from one substrate to another occurs, this is known as an inoculation. Transfers and inoculations are forms of propagation; or increasing the number of fungi cultures. Most fungi prefer materials such as straw, sawdust, cardboard, paper, woodchips, or even compost for fruiting substrates.

Top: Grain jar uncolonized, a simple mass of individual grain kernels (spawn substrate)(Voss Picture)Bottom: electron microscope of mycelium (www.indiegogo.com)

This excess step is to make sure no unseen contaminants are persisting.

2. Ample time is given for mycelia to colonize contamination free.

3. The isolation should be transferred to another petri dish in the same format described on the left side of this page.

of grabbing mycelium from the top gills, or the bottom stipe.

1. Instead of transferring culture to culture, use a scalpel or another tool to grab a piece of white mycelium from the stipe (stem) and place in the petri dish. If the stipe is not offering prominent mycelium, samples can be taken from the spore-heavy gills on the bottom side of the mushroom cap. The picture above features a diagram

samples can be isolated directly from specimen of fungi in the wild, from a friend’s, or from one that is to be cooked for dinner.

For the more ambitious individuals,

What Materials Do I Need to Begin Spawn Production?Autoclave or Pressure Cooker Allows one to sterilize media of

contaminants before inoculationHEPA Fume Hood HEPA: High efficiency particulate

arrestance This allows one to work in sterile

conditions while transferring mycelium from growing media to new growing media.

Room should be kept sanitary as much as possible

Sterilized Petri Dishes There are many agar, malt, yeast

combinations that can be combined with other chemicals to maximize selection for fungi while avoiding contaminants

Sterile tissue technique tools Scalpel, Bunsen burner, tweezers Ethanol or other sterilizing agent

Standard sized Mason Jars (Bottles) Cut two small holes in top for air flow

Microporous filters Placed between lid and jar to allow air

flow that withstands contaminants Mushroom culture or live mushroom specimen to be cloned

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have competition over mycelium will then substrate, the jeopardizes spawn or

other fungi in my mushroom cultivation practice?*The mushroom cultivator is not trying to replicate an ecosystem in all of its complexities, but instead replicate an environment for one specific fungus to flourish. If even a single contaminant

So if fungi occur naturally outdoors in diverse ecosystems, then why do I have to be so careful to avoid bacteria and

contaminated, your spawn is garbage.

contaminants. Once will transfer Contaminated spawn bags, or substrates of any caliber.

The most essential aspect of producing mushroom spawn is avoiding contamination at all costs. One should be very thoughtful to keep a watchful eye for pests, and unclean looking bacteria in your petri dishes, jars,

Note :

While generating Mushroom spawn, the primary goal is to establish healthy, contamination free mycelium, which is ready to inoculate. Spawn transfers always lead to more vegetative mycelium, but once applied to the correct substrate, fruiting will ensue. Quality spawn is of the utmost importance while attempting to fruit mushrooms.

First, Some Basic Myco-Vocabulary

Simplified SubstrateSpawn Substrate: better triggers growth of vegetative mycelium Fruiting Substrate: better triggers growth of mycelium leading to healthy fruiting bodies

What’s the Big Deal With Contamination?

HEPA Fume Hood Diagram showing function (http://www.baylor.edu/content/imglib/1/9/4/6/194643.jpg)

Standard autoclave used to pressure cook substrates of contaminants (http://www.zirbus.com/autoclaves-laboratory.png)

Right: Mason jar infected with Bacillus sp.Left: cap infected (unknown)(www.shroomery.org/)

Clean Culture Transfer Mushroom Isolation

While this brochure will touch slightly on mushroom fruiting techniques, the primary goal is to emphasize mushroom spawn cultivation.

The discussed techniques are in regard to cultivation techniques in a sterile lab production scenario outside of nature.

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After the Petri dish is completely colonized, transfers to jars full of spawn substrate will follow.

Again done under your HEPA Fume Hood, like all inoculations of new, sterilized substrate:1. Simply cut the Petri

plate into wide chunks (some like to cut the circular plate into 8 slices like a pizza)

2. Drop the slices of mycelium into your sterilized jar of grain. Leave about 2 inches free to allow mixing of grain upon inoculation.

3. After the jar is propagated, seal with microporous filter between the jar top and lid.

4. Shake mycelium throughout jar to evenly distribute

It should be noted that the importance of moisture content of your grain cannot be overemphasized. Grain should be soaked for 12+ hours before autoclaving and inoculation. The grain will soak up a large amount of water necessary for mycelium

After your jar is inoculated, precaution should be taken to shake the bottle in a way to spread the slices evenly throughout the grain substrate. Instead of allowing the mycelium to all be in one place, rearranging positions of mycelium throughout the jar will lead to more points of inoculation and a faster colonization throughout the whole. After one week, the jars will be near fully colonized as shown in the above picture. After one and a half weeks the jars will be ready for transfer once more. [7].Post colonization, the grains will be fused together by the dense network of mycelium laid throughout. Before transferring, the jar should be smacked around and shaken up to break up the grains until they are freely moving once again. This breaking of the mycelium creates a vast amount of inoculation points on every mycelial piece that aids in faster colonization on the next propagation step. At this point you have now successfully made grain spawn! After colonization, this mycelium has established vegetative tissue for some time, and is ready to spread its spores via fruiting! If your attention to detail and contamination has made it this far, there is good chance you’ll be fruiting mushrooms in no time!“The art of propagating mushrooms is primarily the art of transferring the mycelium from one food source to another to keep it going as long as possible.”

-Edmund Williams

Grain spawn jars partially colonized (Voss photo)

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Jar to Jar: More Propagation, or Fruiting!

Jar TransfersJar to Jar transfers can be utilized in generating more spawn, or to begin the fruiting stage with Bottle Culture. Whether generating more spawn, or beginning fruiting, the technique is the same, but the difference lies in the substrate. Transferring bottled grain spawn to a bottle with adequate substrate is a pretty simple process.

1. Under a HEPA fume hood, shake to break up the mycelium in colonized jar

2. Pour broken up spawn into a new jar with preferred substrate that has been sterilized. (Keep a little space at top so mixing sealed jars is possible)

3. Seal jars with lid and microporous filter.4. Shake to disperse spawn evenly.

One of the major benefits of bottled grain spawn is that it affords the possibility of further propagation in large amounts if desired. One bottle of completely colonized grain spawn can be used to inoculate ten more bottles. Imagine having ten jars of colonized grain spawn; it is very possible to make a quick jump to one hundred bottles if every bottle inoculates ten more. Likewise, fruiting substrates in jars can also be inoculated for high amounts of mushrooms.

Jar to jar transfer can be used to spur Bottle Culture fruiting, or to continue building up a spawn collection for future fruiting.

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The primary focus of Bottle Culture is to fruit mushrooms from the bottle, not to make more spawn. Before attempting to fruit from the jar, one should be aware that certain fungi fruit better from jars than others, research is necessary. Instead of grain spawn throughout, ample substrates such as sawdust are preferred for fruiting. After sterilization of the bottle with the sawdust inside, grain spawn is often used to inoculate bottles in a quick and efficient way. After inoculation, the jars are shaken and given warm and dark environmental conditions until the jar is colonized. Once colonized, the lid is taken off the jar, humidity is raised, and light is introduced to the culture to trigger fruiting.

Bottle culture often leads to uneven colonization throughout the jar based on dispersion of inoculum grains. This usually leads to the top of the jar colonizing before the bottom. This is beneficial in that the oldest mycelium produces the fruiting bodies, but the mycelium at the bottom of the jar is never able to fruit upon reaching maturity. This method does not maximize fruiting, but offers a very quick, efficient, and smooth operation [8].

If any contamination of the smallest degree is found in a jar, that jar should be discarded. As continual propagation steps occur, the contamination will manifest in larger amounts further down the line.

Fruiting: Bottle Culture

By: Samuel Voss vossx209@umn.edu

Final ConsiderationsMycology is an ever-growing field that is undergoing revolutionary cultivation techniques annually. Part of the fun in caring for fungus is the creativity the cultivator can explore in maximizing their product. Whether experimenting with the wide array of different species, altering substrate to see what the fungus prefers, altering environmental conditions, or simply foraging in a forest, there are many routes to taking up a myco-hobby for enjoyment. Furthermore, after the mushroom growth experiments are concluded, everything involved in the equation will be compostable if organic compounds are strictly used! This brochure highlighted a very direct and distinct avenue of mushroom grain spawn cultivation while also touching on one fruiting technique, yet there are many more avenues available in producing mushrooms including bag spawn fruiting, outdoor patch inoculations, tree stump inoculations, and straight log inoculations to name a few. While there are many ways to cultivate fungus, quality spawn is necessary for any growth of value to occur. Sterile tissue technique to grain spawn is a tried and tested way of producing highly efficient mycelium spawn in a format that can maximize quality and quantity. By learning to control contamination variables, the

Top picture: bags of ash sawdust before being autoclaved, will be inoculated with oyster mushrooms after. (Voss Picture)

Picture of the author holding PoHu Oyster cluster (Pleurotus ostreatus) and a large Lion’s Mane fruiting body (Hericium erinaceus)

Endnotes1. Liang, Z (2014). "Ganoderma lucidum polysaccharides target a Fas/Caspase dependent pathway

to induce apoptosis in human colon cancer cells". Asian Pacific Journal of Cancer Prevention 15 (9): 3981–3986.

2. Teng, BS (2012). "Hypoglycemic effect and mechanism of a proteoglycan from ganoderma lucidum on streptozotocin-induced type 2 diabetic rats.". Eur Rev Med Pharmacol Sci 16 (2): 166–75.

3. Zhang, R (2011). "Ganoderma lucidum Protects Dopaminergic Neuron Degeneration through Inhibition of Microglial Activation.". Evid Based Complement Alternat Med. doi:10.1093/ecam/nep075

4. "Antimetastatic effects of PSK (Krestin), a protein-bound polysaccharide obtained from basidiomycetes: an overview". Cancer Epidemiol. Biomarkers Prev. 4 (3): 275–81. 1995. PMID 7606203

5. Wasser, S.P., 2002. Medicinal mushrooms as asource of antitumor and immunomodulating polysaccharides (minireview). Appl. Microbiol.Biotechnol., 60: 258-274.

6. Stamets, Paul. Growing Gourmet and Medicinal Mushrooms. Volume 3. Berkeley: Ten Speed Press, 2000. 94-96. Print.