How to Grow Shiitake Mushrooms in a Cold Climate and Why You Should

Shiitakes are a powerful source of food, medicine, and experience in our lives. They were the first mushroom I ever learned how to grow, and made me fall in love 100% with mushroom cultivation. Learning to harness the growing energy of these beings is great medicine all on its own. The powers of fungi will mystify and inspire you. I hope this article opens you up to what is possible in the world of growing fungi. Enjoy the rabbit hole you are now falling down!

Fungi are truly their own organisms; there aren’t many things out there that literally eat the lignin of wood, interconnect the entire forest, and decompose everything into nutrient rich top soil. Partnering with Shiitakes and learning to grow them is like taking all of those tree connecting, soil making, food producing abilities they have and feeling them within.

Not only are Shiitakes an amazing food, they teach you things about the world that deepen your perceptions and understanding. When I first started learning about them, I started to feel and see the power of fungi in almost everything. Their incredible lessons of life have unique opportunities for our health and the world. Growing them as a food is really only the beginning of their potential. Everything from textiles, to building blocks, to plastic alternatives are being explored right now.

I’m getting ahead of myself! It’s just all too exciting.

Growing Shiitakes is a simple process in a cold climate, and with some guidance you will be well on your way to fresh mushrooms. This process requires a shady spot, a few tools, freshly cut tree logs (or not more than 3), and Shiitake spawn. What is mushroom spawn you ask? Mushroom spawn is essentially any substance like saw dust or wood chips that has been inoculated with the mycelium of that specific mushroom.

I like to think of fungi kind of like an apple tree. The mycelium is the tree, where as the mushroom is the apple. Once your logs are inoculated, you can sometimes get up to 9 years of mushroom growing depending on the type of wood you’ve chosen.

How to Grow Shiitakes; Step by Step

Tools/Things You Need

-Mushroom Spawn
-Inoculator Tool
-Corded Drill or Angle Grinder
-Soy Wax
-Logs (see details below)
-Shady location (or use a tarp)
-Source of water close to mushroom site

1. Harvesting Wood; When to Harvest

There is a lot of mixed perspectives on when is the best time to harvest the wood. Some people suggest to harvest the wood in February-March because the sap isn’t flowing yet. This is so that the bark won’t slip when you drill the holes. Other research suggests that it is best to harvest when the sap is flowing because the sugar content of the wood is higher.

However, there is plenty of research out there that suggests that it doesn’t really matter when you harvest the wood, as long as you inoculate it within 3 months and absolutely ensure the wood has not dried out! I made the mistake before of cutting up my wood in late winter and it had dried out too much by the time I had to inoculate. You can keep them in a shaded area with some evergreen boughs on them to prevent them from drying out. I always cut my logs in February and have had great results this way in a cold climate.

What kind of wood is best?

A lot of different hardwoods are acceptable for Shiitake inoculation. Some appropriate species for Shiitake cultivation in Northeastern Ontario are; Oak being the best, Sugar Maple is also great, and Birch, Red Maple, Beech are also good. Poplar can be used but it decomposes quite quickly. For all of the effort you put in for your mushrooms, you want a log that will last!

Because Oak is the densest and hardest, it will take the longest for the Shiitakes to eat through the wood. Oak can grow a steady supply of mushrooms up to 8 years! This is also the preferred species of Shiitake in it’s native landscape. The softer the species is, the shorter the time span will be that you’ll get flushes of mushrooms.

What size should the wood be?

Your wood should be 4-8 inches in diameter and about 4 feet long. Pieces that are bigger than that will take longer to be colonized by the mycelium, which isn’t a bad thing if you have time. But they are also harder to move around when they’re bigger than this! Instead of one year, you will perhaps wait 1-2 years if the logs are bigger.

Acquiring your wood:

Bad storms can often bring gifts of trees that you can use for your mushrooms. Arborists often need to get rid of wood and are willing to give it away for free or for a small price. There is also the best option in my opinion; coppicing the wood yourself. Coppicing is a unique and regenerative way of harvesting wood that can allow the tree to live on and regrow. Read my blog post on coppicing to learn how to do this.

There are some important tips to remember when harvesting the wood. If the bark is damaged, it won’t be able to hold in the moisture that’s needed for mushroom colonization. It will also create more room for the log to become colonized by other native fungi. Try to get logs that are in good shape to ensure the longest time possible for the cultivation of mushrooms, as well as to limit the competition from native fungi.

2. Purchase Spawn, Inoculator Tool, and Soy Wax

First, you’ll need to purchase some spawn. I always ask for the spawn to be delivered by late May as this is when we start to have frost free nights for the most part.

Spawn is the mycelium of a mushroom that has been inoculated in wood chips or saw dust. The inoculated wood chips will come in a plastic bag and you will see the thread like white webbing of the mycelium. Companies in Ontario that offer Shiitake spawn include Grow Mushrooms Ontario, Mycosource or Wylie Mycologicals. I usually order one bag which is supposed to have enough spawn to inoculate 25 logs.

It is important to try to use up the spawn within a week to a month, and refrigerate it if you don’t use it right away. This will slow down the mycelium growth and keep it relatively dormant. I’ve read a lot of mixed information, but some sources say that the spawn can stay viable for months when its refrigerated. However, the sooner you use it the better chances you have for viability I’ve learned.

Mycosource also has this really awesome little tool they sell that is for inoculating the spawn into the logs. It’s called a Thumb Inoculator. This is a necessary purchase for mushroom cultivation, and can be used year after year.

If you’re outside of Canada, I recommend Field and Forest products for spawn. They have an incredible range of products.

And finally, purchase your soy wax! This is available at many craft stores, or online. This is for sealing off the holes after you’ve inoculated the logs with your spawn. This will help to keep moisture in, and will help to keep critters out like slugs.

3. Drill Holes

This can be done with a regular drill or an angle grinder. A regular drill works, but it can be a much slower process unless you have multiple batteries ready to go, or just use a corded drill.

You’ll need a 5/16 inch (8mm) drill bit. If you have an angle grinder the process is much faster.

You can also purchase the angle grinder adaptor piece on the Mycosource website, as well as the drill bit with a depth stop.

Drill holes in the log 4-6 inches apart and create a checkerboard pattern. Drill the holes 1-2 inches deep.

4. Soak Logs

Soak your logs in some water, or hose them down intensively for at least 10 minutes. Focus on the ends of the logs, more so than the bark. This will create the perfect environment for the Shiitake spawn to colonize.

5. Inoculate Logs

Before inoculating, ensure the spawn is still moist. Mist with some water if it seems dry. In a cold climate, don’t inoculate your logs too early in the spring season. Moderate frosts won’t kill the mycelium, but harsh frosts could. In Northern Ontario we experience deep frosts up until May, with sometimes many moderate frosts during May. Waiting until the end of May to inoculate is the best way to go.

6. Apply Soy Wax

Many kinds of wax are suitable for this process. You can use beeswax, and many other types of wax. I prefer to use soy wax as it is much more affordable. You can use a paint brush or some kind of sponge to apply the soy wax. Simply heat it up the wax on low heat and once melted apply to the tops of the holes you filled with mushroom spawn.

It helps if you have an outdoor cookstove for this, so the wax doesn’t harden by the time you get outside. Take it from someone with experience, if you live in a slug prone environment like many northern landscapes are, add a thick layer of the wax. Even after one season it is incredible how many slugs and insects are able to eat through the wax.

Another way you can deter them is by encircling the logs with wood ash. However, it needs to be reapplied after rain falls because the water will wash it away. You can also lay down copper piping around your logs. The slugs experience a chemical reaction when they cross over copper that is unpleasant to them, so they do everything they can to avoid it.

7. Find a Shady Spot

Before putting your logs in an area, do a thorough examination of the suns pathway. Shiitakes require full shade. The thick canopy of an evergreen in a north facing area of the forest will shade them out quite well, even in early spring when the deciduous leaves haven’t emerged yet.

If you don’t have access to full shade, use a breathable material to shade them out. If all you have is a tarp, ensure there is a buffer layer between the tarp and the mushroom logs so as not to encourage mold.

8. Stack the Logs

The best way to stack them is a sort of lean-to system. Lean them up against trees, or grab a long piece of wood and nail to several different trees so that you have something to lean the logs up against. Shiitake logs do well to have one end touch the ground, which encourages mycelial growth.

If you don’t have a lot of room, you can also stack them in a sort of crib like system one on top of the other. This will also make them easier to protect from slugs as well.

9. Watering

In our environment we water our mushroom logs once a week. How often you water is very reflective of the kind of climate you live in. It is better to soak the logs in water for a couple of minutes, than misting them. If you can find a little creak near by or if you have an old tub you can use to soak them in, try that!

If all you can do is water them with a watering can that is fine, too. Just try to give it a long deep watering. If you live in an area where there’s relatively frequent deep rainfall don’t worry about watering as much. In a periods of drought water twice a week. Align your watering with the weather and seasons.

10. Fruiting

Within 6 months your Shiitakes can be ready to fruit. However, it is recommended that you wait longer than that (9-12 months) so that the mycelium has fully colonized the wood. If you’re unsure if the logs are colonized or not, check for patchy discolouration on the ends of the logs. If the discolouration is present, they are colonized!

After 9-12 months, you can soak the logs in water for 24 hours to force them to fruit. Shiitakes are one of the easiest mushrooms to force fruiting, and you can almost guarantee that mushrooms will pop up 2 weeks after soaking. The more you do this, the faster the log will decompose. None of this is necessary of course, and you can just let Nature take it’s course. They will fruit in the spring, and an additional 1-2 times throughout the season in a cold climate. Mushrooms are mysterious beings and fruiting can occur at indefinite times.

Why You Should Grow Shiitake Mushrooms

There are an incredible amount of nutritive and medicinal benefits to Shiitakes. With the mere consideration that these mushrooms actually consume the trees they grow on is enough to muse the endless possibilities of health benefits they have. But aside from all of these gifts Shiitakes contain, the flavour is enough to captivate you alone. It is so beautiful in soups, omelettes, pastas, or as a side. They can be cooked fresh, dried, and frozen in after cooking. They have a lovely woodsy, earthy flavour, that adds layers of complexity to many dishes.

Shiitakes are immunomodulating. This is attributed to their ability to keep our immune systems in check; regardless of what may be out of balance. Their anti-inflammatory abilities are strong, and they have potent anti-viral, anti-tumour, and anti-cancer properties. There aren’t very many things out there in Nature that have this incredible ability to enhance the immune system as well as fight viruses and other chronic diseases.

In addition to all of these powerful health benefits, Shiitakes are known to lower cholesterol levels through regular consumption. Supplementing our diets with Shiitakes and other medicinal fungi can be so advantageous to our well being. They are incredible allies to us in an age of so many pollutants and toxins surrounding our day to day lives. The more I learn about Shiitakes, and fungi at large, the more I am allured by their mystic nature. Facilitating growth for these beings is a powerful experience that is beyond words.

Shiitakes are also high in Vitamin D, and can actually soak up Vitamin D when you allow them to dry in the sun. Sound familiar? These qualities are a lot like us humans! Plus, they have high levels of protein and other minerals, and are a great alternative for anyone who doesn’t consume meat. Without the need for pollinators, sun, additional fertilizers, and with a 3-9 year return, growing Shiitakes in a cold climate offers a resilient food opportunity.

Business Opportunities

Economically, Shiitakes can be sold for a premium to restaurants, or can be dried and sold commercially that way. It is well known that Shiitakes grown on logs taste much better than ones grown in commercial labs. You can sell them for a premium when grown in the natural forests that surround us. They currently sell for $12 a pound fresh, and $6 a pound fresh wholesale. You can also sell them dried and can get $22 a pound retail, and $12 a pound wholesale. They’re some of the most profitable mushrooms you can grow, and are only gaining in popularity in North America. They are a great way to make the most out of a forest landscape where you live, provide food for your family, and potentially create an avenue of income. If you’re interested in the logistics behind growing Shiitakes as a business, read the book Farming the Woods. There’s a great break down of someone who went through the motions of turning Shiitakes into their livelihood.