Grow Shiitake Mushrooms at Home: A Walkthrough

I am fascinated by mushrooms. I have always found them to be not only beautiful, but delicious! Gourmet cooking can incorporate mushrooms in many different ways, and growing them yourself is half the fun. By reading this guide you can start a project yourself and successfully grow your own Shiitake. Growing mushrooms is an extremely fun hobby or family project. While it is enjoyable and rewarding, growing mushrooms is not a hobby for those who like instant gratification. Not too much work is involved, but the process of growing Shiitake mushrooms from beginning to end can take up to ten weeks. The process will usually only take around seven weeks, however. There is a large amount of variability in time frames when growing mushrooms. There are many factors to consider, such as humidity, temperature, substrate nutrients, and last but certainly not least, the genetics of your particular strain of mushroom. There is nothing like watching the process of a mushroom grow from start to finish. Most people don't realize what goes into mushroom growing or even understand the general anatomy of a mushroom, so we'll start there first!

Many people assume that a mushroom just grows out of the ground when it rains. While this is strictly true, the story starts well before then. While a mushroom does grow out of the ground after a heavy rain, the real organism has been growing underground (or inside wood in the case of a wood lover) for anywhere between a few days to a few years depending on the species. Most people know that mushrooms drop spores. When two spores from the same species meet, they form a mycelium, which continues to grow. The usually unseen body of the fungus is called the mycelium. Mycelia are composed of a stringy network of hyphae, which are like little fingers that spread through the substrate. Many people do not know that fungi are more closely related to animals than plants! The hyphae secrete digestive enzymes to break down the nutrients in the soil or wherever they have been growing. After the mycelium grows and develops, it will produce mushrooms to drop spores for the purpose of reproduction. The mushroom is to a fungus as a flower is to a plant. It's fascinating stuff!

This guide is intended as an introduction to the hobby of growing edible mushrooms. Learning from and following the guide will give you the knowledge and ability to grow your own edible mushrooms. There are more advanced techniques and countless other species of mushrooms available for cultivation that I did not feel necessary to include but are invaluable to commercial edible mushroom growers, such liquid cultures, agar work, and strain isolation. There are also many other techniques for growing different species of mushrooms, like spawn logs, straw logs, grains, casing, and outdoor grows. If you follow the guide and had fun cultivating Shiitake mushrooms, by all means do some research and start experimenting with new methods and species. For a hobbyist making his first attempt at a grow or as a fun family project, these things are unnecessary and the hobby is still a blast!

If you're interested in more advanced mushroom cultivation, check out the excellent video series "Let's Grow Mushrooms!" by Marc R. Keith.

Don't let the following list intimidate you. The materials are inexpensive and the process is quite simple if you break it into steps and follow along closely. I will also provide links from Amazon for all the required materials along the way.

Shiitake culture
1/2 Pint Wide Mouth Canning Jars
Brown Rice Flour
Mixed Bird Seed
Vermiculite
Kebab Skewers
Rubbermaid or Sterlite Tub
Perlite
Power Drill

Optional:
Pressure Cooker
Blender/Coffee Grinder
Thermometer
Hygrometer

I will do a brief review of each item on the list. Don't worry if you feel you don't know enough about them, I will post detailed instructions further along in the guide.

-Shiitake culture: the most important item you will need. You won't be growing Shiitake mushrooms any time soon unless you have a culture.
-Canning jars are used to hold your substrate and where your mycelium will grow until they are birthed.
-Brown Rice Flour is the main nutrient of your substrate, what the mycelium will feed on.
-Mixed Bird Seed is the other source of nutrients.
-Vermiculite is a mineral that holds moisture well and helps to bind the substrate together as the mycelium clings to it.
-Kebab Skewers will be cut into small sections and used as a cheap source of wood dowels that the mycelium will break down and consume.
-The tub will serve as your terrerium, or fruiting chamber, by holding in humidity while also allowing for a small amount of air flow.
-Perlite is similar to vermiculite in that it is a natural mineral that holds water. It is used to maintain the high relative humidity in your fruiting chamber.
-A Power Drill will be used to drill holes in your terrarium. While this is not strictly necessary, I would not want to be without one.

-Pressure cooker is for pasteurizing your substrate before inoculation more easily. It is not necessary, but quite helpful. A large pot can be used instead.
-A blender or coffee grinder makes grinding the bird seed extremely easy.
-A thermometer is used to help keep track of the temperature in your terrarium and see if it is within the proper range.
-A hygrometer is used to help keep track of the humidity in your terrarium and see if it is within the proper range.

Now that you have all the materials you need, let's get started!

Getting yourself a culture is the one sticking point on the list of materials. You won't find them in a grocery store or hobby shop, so purchasing them online is necessary. There are many spore and culture vendors online, and I will provide a short list of reliable vendors. What you will be ordering are not spores, but what is called a liquid culture. The spores have germinated and the mycelium has been growing inside of a nutrient laden liquid. This makes for faster growing upon inoculation since the mycelium has already begun growth. Here are some options for your Shiitake cultures:

http://www.freespores.com/lentinula-edodes-shiitake-mushroom-strain-wvm075-p-91.html

http://www.ralphstersspores.com/USA/product_info.php?cPath=10&products_id=264

There are a large variety of spore vendors online. Feel free to look around and see if you can find one you like better.

To preface this section, I need to stress the importance of getting wide mouth jars. If you choose not to use my Amazon link and get them on your own, please ensure that you buy 1/2 pint wide mouth jars. If you buy regular instead of wide mouth, you won't be able to take your cake out of the jar and wind up having to either smash the jar to get the cake out or destroy the cake to keep the jar, not a good situation either way. Moving on to substrate jars, now we're really getting somewhere!

To prep your jars, take off all the lids and lay them down. Either use a drill or use a hammer and nail to punch four approximately 1/8 inch holes. Think of the lid as a clock. The holes should be at 12, 3, 6, and 9 o'clock. And now we're done! That was simple.

For the next step, mixing your substrate, you will need a large mixing bowl and your substrate ingredients (Brown Rice Flour, Wild Bird Seed, Vermiculite, Kebab Skewers). The proportions are constant but amounts depend on the number of jars you plan on using. I recommend going for a dozen because you should expect to lose one or two to bacterial or fungal contamination (more on that later) or it may simply stall and stop growing. By following proper procedure and inoculating 12 jars, you are almost guaranteeing at least 9 successful cakes. Each jar is 1/2 pint and will not be completely filled, so we're looking at about 2/5 of a pint of substrate per jar. Keep in mind that there are eight pints per gallon when mixing your substrate. The substrate will be mixed in the following ratio: 1/2 vermiculite, 1/4 bird seed, 1/4 brown rice flour. Try to aim for as close to these proportions as you can, though getting it perfect is not necessary. I will be giving amounts assuming you are using 12 jars, but it is simple to adjust accordingly.

For the first step, take your Wild Bird Seed and grind it in a coffee grinder or blender. It doesn't have to be a perfect floury powder, but make sure there are no large chunks. Make sure it composes about 2.4 cups (or 1/4 of your necessary substrate). Next, add the same amount of brown rice flour. After this add 4.8 cups of vermiculite (or double your volume of substrate with vermiculite). Slowly add water and mix by hand. The goal is to get the substrate to field capacity, which means if you squeeze it it does not drip water (or only 1-2 drops), but should be thoroughly saturated. Scoop this mixture into your jars in even amounts. Once your jars contain the mix of saturated substrate, cut or break your skewers into approximately 1.5 inch sections. Insert 6-8 of these 1.5 inch sections of skewers down into your substrate in each jar. Space them out approximately evenly through the jar. Each of your jars should be nearly full but not quite to the top. Take a paper towel and clean the space that you left at the tops of the jars, making sure there is no substrate sticking to them. To finish each jar, add a small, approximately 1/2 inch, layer of dry vermiculite to the top of each jar. Screw the lids back on your jars. Take pieces of aluminum foil and tightly cover the top of each jar (this is to make sure no moisture gets in through the holes during the pasteurization process).

Now, we will pasteurize our substrate jars to kill all the contaminants.Take your pressure cooker (or large pot with a well-fitting lid) and make sure nothing can touch the bottom. Many pressure cookers come with a wire rack to prevent this, but if necessary use jar rings or wads of aluminum foil. If you fail to do this, your jars will probably crack during pasteurization. Add your jars to your pressure cooker/pot (if your pressure cooker or pot is not large enough, this may take two loads) and add cool water so that it almost comes up to the bottom of your jars. Put on the lid and turn on the heat. Once the water comes to a boil (pot) or the rocker starts swaying (pressure cooker), turn the heat down to simmer (pot) or to the point where the rocker continues a slow sway (pressure cooker). At this point, set a timer for 90 minutes (pot) or 60 minutes (pressure cooker) depending on which method you are using. Once the timer goes off, remove the pot or pressure cooker from your heat source and allow to cool for eight hours. It is best to start this process in the evening and wait overnight for your jars to cool. Once cool, remove your jars from your pressure cooker or pot and take the foil off the tops when you are ready to inoculate.

Alright, it's time to inoculate your substrate jars with your liquid culture (from here on I will be calling it an LC). First things first, wash your hands to prevent contaminants. Take your LC syringe and remove the cap. Take a lighter and hold it over the needle until it is red hot to make sure it is sterilized. Wait for it to cool and insert it into the first hole of your first jar. Squirt 1/4 cc of LC into the hole and then move onto the next hole. You should be adding 1/4 of LC into each hole, or 1 cc of LC per jar. Repeat this process for each of your jars. If you ordered a 10 cc LC syringe and are choosing to do 12 jars, don't worry, just add very slightly less than 1 cc to each jar and you will be fine.

Up to this point may have seemed like a lot of steps, but it's not much work, right? Alright, after your jars have been inoculated, keep them in a cool place. It does not need to be dark. In fact, a bit of ambient light can help growth. Check on them every few days. You should start to see white spots growing out radially approximately below each inoculation point. Don't be alarmed if brown spots begin forming on the outside of your cakes, as Shiitake mycelia will produce a 'bark' around itself sometimes. This will not always happen when growing them in jars, but is extremely common. From the time you inoculated your jars to when they reach full colonization can be anywhere between two and five weeks depending on any number of factors, just keep checking on them. When it looks like the mycelia have completely colonized all of your substrate, this is called full colonization. At this point, give the mycelia one more week to sit there. This is called a consolidation period. After the consolidation period is over, we will begin what is called the cold shock. Take your jars and put them in the refrigerator. Be sure that your refrigerator is not too close to freezing or it could kill the mycelia. Leave them in the refrigerator for approximately three days.

This next part is called birthing. Gently coax each cake out of your jars. Be very gentle as a cake can crumble or crack if you are not careful. This may take a bit of work, as they are prone to sticking to the jars. As you get each cake out of its jar, place it on a clean surface. A kitchen counter is not recommended unless it has been thoroughly washed and disinfected. Laying them out on a sheet of aluminum foil is fine. Brush the layer of vermiculite from the top of each cake if possible. Don't be too aggressive, if some pieces are stuck in the top of the mycelium, just leave them there, it is not a problem. We are only removing the loose bits. After your cakes have been removed from their jars, gather a large pot (possibly the same one you used to pasteurize your jars) and fill it with cool water. Submerge your cakes in the water and make sure they stay submerged, using a weight and some mesh or screen or some other method. Leave them soaking there for about 24 hours.

Alright, we're almost done now. All that's left to do is construct a terrarium and add your cakes!

The type of terrarium we will be using in this guide is informally known as the shotgun fruiting chamber, or SGFC, because it is full of holes. The basic idea is that by drilling rows of holes throughout your fruiting chamber you allow enough fresh air exchange to occur, while keeping the holes small enough to retain the humidity inside the chamber. The fruiting chamber is created from any sort of transparent Rubbermaid or Sterlite tub. The size of the tub depends on how many cakes you plan on fruiting in each tub. Generally multiple smaller tubs will perform better than one extremely large tub due to the differences in the rate of fresh air exchange between a small and large tub.

Different growers will say to use different size drill bits between 1/8 inch and 3/8 inch. For construction of this SGFC, a 1/4 inch bit was used. Intuitively, the bigger the bit you use the less holes you should drill, and the smaller the bit you use the more holes you should drill. This is not an exact science and there is a lot of room for error. On this SGFC, holes were drilled approximately two inches apart along each surface of the bin. All six sides need holes.

Once the holes have been drilled, open your bag of perlite. Take a kitchen colander and fill it with perlite. Rinse, wash, and soak the perlite thoroughly, and allow it to drain. After the perlite has drained (no more water dripping out of the colander), dump the perlite into your fruiting chamber. Repeat this step as many times as necessary until you have a 4-5 inch thick layer of perlite on the bottom of your tub. If you allowed the perlite to drain well, there should be little to no water leaking out the bottom of the tub. If you are worried about leakage, simply set your tub on a towel during this step.

After the tub is fully prepared, place the lids from the your spawn jars upside down in the pattern you'd like to have your cakes laid out in. Remember, don't crowd them in too close to each other because you will have mushrooms up to six inches long growing out of the cakes. Take your pre-soaked and cold shocked cakes and place them on top of the lids, using the lids like little tables to keep the cake from directly touching the perlite. After the cakes have been set inside your fruiting chamber, simply put the top on. At this point you are almost done!

There is a simple visual walkthrough in the picture guide below if you're having trouble visualizing the process.

After you place your fully colonized cakes in your terrarium, you're on the home stretch! The term 'fruiting' is used to describe a mushroom growing out of the mycelium in the same way 'flowering' is used to describe a flower growing off of a plant. Like I mentioned in the colonization section, don't be alarmed if your cake starts to turn brown and crusty looking after being transferred to your terrarium, it is perfectly normal for Shiitake mushrooms to produce a 'bark' around the mycelium. This is not a good or bad sign, as they do not always produce a bark when grown on cakes and can still be perfectly healthy.

The ideal place for a terrarium is in a basement in houses in the north if you are growing in the US. It is easy to maintain humidity and a cool temperature in a basement. Cultivation of Shiitake mushrooms is not possible in all climates without refrigeration or air conditioning, so keep this in mind before beginning a project. Also keep in mind that mushrooms need light to grow, much like plants do (though for different reasons). Shiitake prefer indirect natural light, so a location near a window would be ideal. If kept indoors away from windows, the light cycle can be replicated by a sufficiently bright compact fluorescent light bulb (cool white) being kept on for approximately 10 hours a day, and off for approximately 14 hours a day. The light cycle in this case would be called 10/14. This can be tweaked and is not necessary to follow it exactly. Anything between 8/16 and 12/12 should be fine.

Here's where the optional use of the thermometer and hygrometer come into play. Keep a thermometer and an analog hygrometer (be sure to calibrate it) inside your fruiting chamber to get accurate results. To induce pinning (a pin is the term for a little baby mushroom), an ideal temperature range of 55-65 degrees Fahrenheit and relative humidity of as close to 100% as possible are recommended. At close to 100% RH, there should be condensation coating the walls of the terrarium and your mushrooms and cake should appear moist. If your terrarium seems dry, open the lid and gently mist the entire inside of it with water from a spray bottle. Make sure not to overdo it, though, as standing water in your terrarium is never a good thing. While mushrooms can and will form outside of these ideal ranges, performance will not be ideal and fruits are at a much higher risk of either mutating, being very small, dry and withered, or aborting in the early stages of development. After sitting in the proper fruiting conditions in your terrarium after their soak and cold shock, your Shiitake cakes should begin pinning in 2-5 days. You should expect to see between three and over a dozen pins on each cake.

After they begin pinning, the ideal temperature range changes to between 55 and 75 degrees with a relative humidity of between 60 and 80%. At 60-80% RH, there should be a good amount of condensation visible on the walls, but noticeably less than in the pinning stage. Again, if your terrarium seems dry, open the lid and gently mist the entire inside of it with water from a spray bottle. If all has gone well, the mature fruits should be ready to harvest in 1-2 weeks. To harvest, simply take a sharp blade and slice the mushroom off the cake at its base. Congratulations, you have grown your first mushroom!