I’ve always been a mushroom-lover… blame it on my upbringing. I grew up in the woods, with two generations of wild mushroom foragers before me. I’ve eaten a lot of really amazing fresh mushrooms in my life- and while I love foraging for them, it’s even better to be able to grow Shiitake mushrooms in our own backyard!
Growing mushrooms has been one of our most rewarding homestead endeavors! They’re a fantastic “crop” to grow in the shady places where nothing else grows!
Watching the mushrooms pop out of the logs every year is truly magical. And what an incredible resource! While I won’t go into the health benefits of Shiitakes here, know that they have been widely studied and have proven themselves to be an incredible superfood.
And if that isn’t enough, they are quite tasty too! I love love love being able to grow shiitake mushrooms in our own backyard!
We are amazingly fortunate to have a mushroom growing mentor in our lives- a commercial mushroom grower and mushroom foraging expert nearby us, which is how we learned to grow Shiitake mushrooms. Taking a hands-on class from a guy who grows thousands of pounds of mushrooms every year was invaluable… so I’m sharing what we learned with you in great detail!
Looking for Ready-To-Grow Logs or Mushroom Grow Bags?
If you don’t want to inoculate your own logs, but still want to grow your own mushrooms, you can buy pre-made logs and ready-to-grow mushroom kits! Check them out —> here!
How to Grow Shiitake Mushrooms Overview – So There Are No Surprises!
Probably the hardest part about growing Shiitakes is moving the logs around. Ours are Oak, and they were a little larger than advised, so moving them was a bear. The actual inoculation is quite fun and could be a great family activity!
Logs are cut from live trees, left to age two weeks, and then inoculated. Inoculation involves drilling holes all over the logs, filling the holes with mushroom spores that are mixed with sawdust, and then sealing the holes with wax. Then the logs are put to bed- they need to be set low to the ground where it is moist, but not on the ground, and covered with straw and something to hold the straw down. There they will sit for an entire year! They will need to be watered weekly if it doesn’t rain. After they have incubated for a year, you can stand them up or stack them, and wait for the mushrooms to come rolling in! Depending on what type of wood you use, the logs will last and produce mushrooms for up to 8 years! They should be kept in shade and watered weekly if it doesn’t rain. That’s it! So simple, and so rewarding!
How Many Mushrooms Will You Get?
It probably varies a lot depending on many things: how well you’ve treated the logs, your climate, the weather, rainfall that year, the type of wood, the strain of mushroom you choose…
I can tell you that we get 10’s of pounds of mushrooms every year, and we have 27 logs that we made from 2, 5.5-pound bags of mushroom sawdust spawn. We haven’t really weighed our harvests, but we collect several large baskets full every year- enough for our needs and then some!
Cost of Growing Shiitake Mushrooms
Here is a reasonable breakdown of the cost to grow Shiitake mushrooms:
Logs: free from the woods
Corded Angle Grinder or Drill: already owned
Angle Grinder Adapter: $30 (only needed if using an angle grinder)
Safety goggles: already owned
Deep Fryer for Wax Melting: $25 (optional)
Wool Daubers: $1-$5
Bale of Straw: $4 (optional)
After the initial investment of the tools and parts, the cost in subsequent years is very low, most likely you’ll just be buying the mushroom spawn after year one! You can easily grow YEARS of Shiitake mushrooms for around $100.
What Time of Year Do You Make Shiitake Logs?
We are in Zone 4 Wisconsin, which means it gets quite cold here. I know that you can inoculate the logs in Fall in some areas- but I’m not an expert on Fall inoculation. It needs to be warm enough for long enough to let the mycelium colonize the logs before they are subject to freezing temperatures.
Here, making Shiitake mushroom logs is done in the Spring after the threat of frost and when temperatures are reliably in the 40s, which also coincides nicely with when the best time to harvest the logs is. Spring is the time when most people make Shiitake logs.
Sourcing and Harvesting Logs for Shiitakes
There are many species of trees that you can use for growing mushrooms. Each different species will give you slightly different results- some types of logs produce mushrooms faster, some logs last for a longer time, and each different wood imparts a slightly different flavor in the mushrooms. We used White Oak, which is the top recommended type of wood for growing Shiitakes.
Superior: All species of Oak, especially White.
Recommended: Alder, American Beech, Blue Beach, Hornbeam, Ironwood, Hard Maple (Sugar), Sweet Gum
Satisfactory: Basswood, Bitternut Hickory, Butternut, Sulpher Bud, Black Birch, Paper Birch, Black Gum, Tupelo, Cherry, Eucalyptus, Soft Maple (Silver & Red), Sassafras, Sourwood.
Superior = best overall producer. Recommended = highly suitable. Satisfactory = moderately suitable.
Wood type information courtesy of Field & Forest.
The logs need to come from trees that are ALIVE. This is vital. Do not use dead, fallen, or previously cut wood.
The ideal size for Shiitake mushroom logs is 36 to 48-inches long, and 3 to 8-inches in diameter. Mushroom logs can be made from both the trunks of young trees, or branches of older, bigger trees.
It is better to choose trees that don’t have slipping or damaged bark, or blemishes. Sometimes when you fell a tree it will get injured and you can’t help it; be as gentle with the logs as possible. Any defects in the bark will need to be coated in wax, so it’s best to keep those to a minimum.
The logs should be harvested when the trees are dormant. This means in the period of time between when the leaves start to turn color in Fall to when the buds start to swell in Spring. Ideally the logs should be harvested as close to inoculation time as possible, otherwise you risk more chance for competing fungi to get in them, and you also have to keep them in good condition until inoculation time. We stored ours for just over a month before inoculating.
After the logs are cut, they need to be kept moist, and competing fungi must be kept out- the best way to accomplish this is to keep them in the shade and secure a tarp over them.
Use the logs within two months of harvesting. If it is Winter and the logs are completely frozen, they can be stored for six months as long as they are protected from wind and sun.
Aging the Logs
I know I just said to harvest as close to inoculation time as possible… but you will also want to let the wood age. Once the logs are cut, you need to let them sit for at least 2 weeks before inoculating. This allows the cells of the tree, which are anti-fungal when alive, time to die.
Choosing A Mushroom Spawn Variety
“Spawn” simply refers to a medium that has been inoculated with mycelium. Mycelium is a collection of thread-like mushroom cells. If mushrooms were a vegetable, mycelium would be like the plant they grown on.
There are three categories of mushroom strains to choose from:
Wide Range Shiitakes will fruit when the temperature is generally between 50-75F. These varieties will take one year to incubate before fruiting for the first time, though you may see fruiting as soon as 6 months (we did!). These varieties are the easiest to grow, most forgiving, and are recommended for beginners.
Cold Weather Shiitakes will fruit when the temperature is generally between 45-60F. These varieties will take one year to incubate and then another year before fruiting for the first time. Up to two years before you’ll get mushrooms! Why bother? Cold weather stains are said to be both the most beautiful, and also the richest, best tasting varieties!
Warm Weather Shiitakes will fruit when the temperature is generally between 50-80F. These strains are said to favor soft hardwoods, so may be a better choice if that is the wood you are working with.
Here is a great chart from Field and Forrest with even more detail on the individual strains to help you choose.
Sourcing good quality mushroom spawn can make a huge difference in your ability to grow Shiitake mushrooms. I would recommend buying directly from a reputable producer, and not from a third party seller. We get our mushroom spawn from Field & Forest, which is also where our mushroom mentor gets spawn for his commercial operation.
We are growing the wide range “West Wind” strain, and the cold weather “Bellwether” strain.
The sawdust spawn should be in a sealed bag and be fairly moist when it arrives to you. It’s okay if it has white stuff growing all over it (thats the mycelium!) just throw that in the mix to be used also. Follow the directions on the bag, which should say to refrigerate the spawn from the time you get it, until you are ready to use it.
How Much Mushroom Spawn to Get?
One 5.5 pound bag will inoculate approximately 25 logs that are 36 to 48-inches long, and 3 to 8-inches in diameter. Of course this is just an estimate and depends on the actual size of your logs. We had quite a few logs that were much larger, so we ended up with less logs overall.
There are 27 logs amongst the three log stacks you see here, which were all created from two 5.5 pound bags of mushroom spawn!
Inoculating the Shiitake Mushroom Logs
The big picture is that we will drill holes all over the logs, fill them with mushroom spores, and then seal them up with wax.
There are a few different ways to go about getting the spores into the logs, and we have only used the sawdust method- which is what I am giving detailed instruction for here. These directions are probably not interchangeable with other spawn types like plug, peg, or thimble spawn.
Once you drill holes in the logs, the inside of the holes will start drying out FAST. You’ve also opened the log to all the spores that could be floating around in the air- so you need to stuff and seal the holes immediately. You absolutely should not drill the holes and then finish the logs the next day, or even later that day.
Karl and I came up with a nice rhythm where he was the dedicated hole driller, I was the dedicated inoculator and waxer, but when he got ahead of me, he would come to my station and help me before starting to drill holes in a new log (since drilling is faster than the other tasks). That way we never had more than one log with holes drilled and waiting at a time.
How to Drill Holes in Mushroom Logs
We used an angle grinder with the angle grinder adaptor, and the drill bit that matches the inoculation tool size. You can use a regular drill, but the difference is that you have to pull the trigger on the drill for each hole. An angle grinder spins continuously, and it spins faster than a drill, so it is much much quicker.
For sawdust spawn we used the 12.5mm Soft Steel Screw Tip Bit With Stop Collar which fits with the brass handheld inoculator we have. Because it has a stop collar on it, it only drills in as far as it is set to, so you don’t have to worry about depth when you are drilling; just push it in until it stops. Karl says it feels like the log sucks the drill bit in, so you don’t have to push very hard.
Be aware that the drill bit size for sawdust spawn is meant to accommodate an inoculator perfectly, and it is not the same size as the drill bit for plug spawn. Make sure your drill bit size matches your inoculator size… they may be slightly different depending on where you buy them.
Safety goggles are a must for the person drilling the holes, because chunks of wood will come flying off the logs!
The holes are drilled about 1-inch deep into the log. Explaining the pattern is harder in words and easier if you look at the picture above first.
Starting at one end of the log and working to the other, drill holes every six inches, starting two inches from the end of the log. For the next row, move two inches down from the first row and start the first hole five inches from the end of the log, again drilling holes six inches apart down the row. Repeat that pattern over and over working all the way around the log- you will end up with a diamond pattern.
Do NOT drill holes into the ends of the logs. DO drill holes into places where smaller branches were cut off the face of the logs.
Karl fashioned a “log holder” out of some scrap wood, which made this process a lot easier! You want the log to be held steady while you drill, but also want to be able to turn it easily as you work around it.
Using an Inoculation Tool to Fill the Holes with Sawdust Spawn
Inculcators come in two styles: palm and thumb, which refers to the body part you’ll use to depress the plunger and release the spawn into the hole in the log. It’s kind of like a big syringe. We tried both types and both Karl and I greatly preferred the palm style.
This tool is what pushes the sawdust spawn into the logs, and if you think you’d like to try using sawdust spawn without one, well just don’t. It is an absolute necessity.
To load the inoculation tool, put a few inches of sawdust spawn into a rigid container- we used a metal coffee can (it was nice to have a cover so we could cover it to keep it moist if we had a lull in the hole filling step).
With a fair amount of vigor, plunge the end of the tool into the spawn several times to pack it in. It’s a good idea to practice filling it and then releasing it into the can a couple times to get an idea of what it takes to make a good “plug” before you start putting it into the log, where its harder to tell if you’ve done a good job. You want it to be packed pretty well with no gaps or air pockets.
With the end of your inoculation tool packed full of sawdust spawn, put the tip of the tool into one of the holes and whack the plunger release button at the top of the tool to expel the spawn into the hole. Hit it fairly quickly to release the spawn in one whole plug; pressing it slowly tended to mess this up for us. You don’t have to hit it that hard, just sharply. This is why I liked the palm inculcator better- it was hard to achieve the sharpness required using just a thumb.
Press your finger over the filled hole to make sure it’s packed in there good.
Repeat about a billion times. :)
We used 1/4 of the bag of mushroom spawn at a time, so that it wouldn’t dry out, and we kept it out of direct sunlight while working.
Sealing the Inoculation Holes with Wax
In order to keep the mushroom spawn moist, and to prevent other spores from colonizing the holes, they need to be sealed. Cheese wax is the recommended wax for this task- beeswax will melt off in hot weather, straight parafin is too brittle and will crack in the cold, and the very soft wax that you can dip your finger in and use with plug spawn is not recommended for sawdust spawn.
Use an inexpensive electric deep fryer, or a dedicated pan on a hot plate for melting the wax. As you may know, once you put wax in something, it belongs to that wax forever. We bought ourselves a dedicated wax melting Fry Daddy for mushrooming! A crockpot was not advised, as it doesn’t tend to get hot enough for wax. Wax + open flame (like a propane burner) is generally not a good idea, so please don’t burn down your garage, mmk?
This is the part of the mushroom log-making process that requires the most finesse and skill. To apply the wax to the sawdust spawn-filled holes, we use wool daubers, which are little metal sticks with wool on the end often used to apply stain to leather.
Dip the dauber about half way into the wax, then apply it to the log. You don’t want too much wax, but you also need to make sure the hole is completely sealed. The motion for applying the wax is a quick but firm tapping over the hole… almost like you’re touching the hole with a magic wand or conducting a symphony orchestra!
If you can tell right away that you didn’t get complete coverage, go ahead and tap on some more wax immediately… but once you get good at it, it should only take one tap to get a complete wax seal, and this is ideal.
One dip in the wax should give you enough wax to seal up a few holes before needing to dip again- with a little practice you’ll be able to tell how many holes you can do before needing to reload the dauber. Move along the log and seal up all the holes. Once you’re finished, put a nice layer of wax over any defects in the bark that expose the wood underneath, chainsaw nicks, or cut surfaces where you removed any side twigs or branches. You can use a rubbing or swiping motion for this.
Do NOT seal up the ends of the logs with wax- the logs need to breath and take in moisture through the cut ends.
Since you’re a newbie, once you’re finished sealing the holes you’ll want to go back and inspect them. Sometimes as the wax dries it disperses oddly and makes the seal incomplete. Put another layer of wax on any holes that are not completely sealed- it is obvious and easy to tell which ones need some more because you can see the sawdust poking through.
Move the finished log aside and allow the wax to completely dry. We stacked our finished logs into a wagon when we were done, so they were ready to haul over to their incubation area.
Because we used two different varieties of Shiitake spawn, we labeled one of the types by stapling some red flag tape to the end of the log so we’d know which were which.
Mushroom Log Incubation
Once the Shiitake mushroom logs are inoculated, they need to be incubated. This is when the Shiitake spores you injected in the holes will grow and colonize the log with mycelium.
Pick a shady spot out of direct sunlight, and line up the logs near the ground but NOT on it. We used some old wood posts we had lying around to set our precious mushroom logs on. See in the picture below how they appear to be hovering just off the ground?
Next, cover the logs with a layer of straw (straw is better than hay, because hay is too green and will break down quickly) to help keep moisture near them. We put a layer of chicken wire fencing over the straw, held down with sticks and rocks, to keep our chickens from scratching the straw off the logs. The erosion control straw mats for covering grass seed are also a great option!
I believe that not everyone covers their logs with straw and this step is somewhat optional. Since this is a very critical time for the logs, we wanted to give them every chance they could get, so we did use straw.
The logs will stay here and incubate for one year! During this time the logs need to be kept moist, so if it doesn’t rain every week you’ll need to water them. We set up a tripod sprinkler for this purpose- they need a good soaking, at least 30 minutes.
Watch for the Spawn Run! And For Mushrooms!
You’ll know your logs are getting filled with lots of good mushroom spawn when you start to see white patches on the ends of them. This was fun to watch for! Not all logs had really obvious mushroom spawn spots, but many did.
We inoculated in Spring, and by Fall while the logs were still in incubation, we found a few mushrooms popping out! That was really exciting!
Set Up Your Shiitake Logs for Harvesting!
After incubating about a year, your logs will be ready to put into harvesting position. It’s okay if it’s not exactly one year, your logs should be well-inhabited with mycelium the Spring following the Spring you inoculated them. They will likely start to fruit quite early in the Spring, so make sure to keep an eye on them and set them up while it’s still fairly cool- we did this around the beginning of April, and we got our first fruiting around the middle of April (of course this will vary depending on your climate and location).
There are a lot of ways to set your logs up for harvesting, probably the easiest is to make a crib or chimney stack, as shown in the photo above. You can also lean the logs up against a tree or a board that is suspended between two trees. Whichever you chose, always make sure your mushroom logs aren’t touching the ground in any way.
Shade is best. It’s okay if they get a little bit of dappled sun throughout the day, but they should really be shaded for the majority of the time.
Shiitake Mushroom Harvesting: Grow Shiitake Mushrooms
The mushrooms will pop out of the holes, and anywhere there is a defect or break in the bark. They will come out of the same holes again and again. Some holes will produce reliably, and some holes sometimes won’t have anything.
A Shiitake is ready to harvest when the veil has broken, just exposing the gills underneath. The veil is a cottony membrane that extends from the cap to the stem and covers the gills. Once the veil breaks, the mushroom will not get any bigger (though it may appear bigger because it will flatten out), and will start to lose quality. The best quality mushrooms are harvested when the gills underneath the cap are just exposed (I test this by feeling under the cap with my finger). It doesn’t hurt to harvest them before this, but if you wait you’ll get a bigger mushroom.
Shiitake mushrooms go from being button-sized to big and harvestable in a matter of days, so check them often when they are fruiting! It’s wonderful and magical and so much fun to watch them grow every day!
To harvest the Shiitake mushrooms, use a sharp knife to cut the mushroom off as close to the log as possible without damaging the bark. Do not “pull” the mushrooms out of the holes.
Always harvest the mushrooms into a breathable container like a basket or a mesh bag.
Refrigerate the mushrooms immediately. Shiitakes will last for a week or more in the fridge, but they start to degrade quickly at room temperature once cut.
The logs can fruit multiple times in the Spring and Fall if conditions are right!
Important note: make sure you know what a Shiitake mushroom looks like and how to identify one. There could be other mushrooms that come out of your logs if other mushroom spores got in there.
Same as when the logs were incubating, they will need to be watered every week if there isn’t a nice rain. They need a good watering, at least 30 minutes, possibly more if it is really dry or very hot. We use a tripod sprinkler, which works very well.
That’s it- now you can grow shiitake mushrooms in your own backyard!
If you use these directions to grow Shiitake mushrooms, please let me know how they do! Either comment here or share your photos and tag me over on Instagram– I’d love to see them!
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