Would you like to know what it takes to have some home-grown shiitake mushrooms? In this article, I will explain a simple method to grow shiitake mushrooms on logs outdoors. This is fun and easy, and anyone can try it. Read on to learn more!
Shiitake Mushroom Log Growing Kit
North Spore provides a simple log inoculation kit for growing various mushrooms, including shiitake. What does their shiitake mushroom grow kit include? Almost everything you need!:
- one hundred shiitake mushroom spawn plugs
- paraffin wax
- one wax dauber
- one 5/16″ drill bit
- a cute little pamphlet on mushroom cultivation on logs using plug spawn
Tools You Will Need to Grow Shiitake Mushrooms on Logs
First, you will need a couple of other tools to inoculate your logs, really just a drill (corded or battery-powered), and a crock pot to melt your wax (Note: do NOT use a paraffin wax bath! It will not keep your wax hot, and it will not end well for you! Learn from my mistakes, k?). If you are inoculating logs by a power source, a corded drill is great. If using a battery-powered drill, you may need to swap batteries or charge your battery. Keep in mind that you will need to drill 100 holes, one inch deep, to accommodate each spawn plug. If you are inoculating in the woods, you’ll need some other kind of heat source to melt your wax.
What Kind of Logs Do Shiitake Mushrooms Grow on?
Shiitake mushrooms, like many fungi, grow on a variety of hardwood species. However, shiitake prefer some tree species over others, and some hardwoods aren’t recommended to use for shiitake. I used beech logs as my substrate. Between you and me, they look infected with beech bark disease. I received these logs sustainably and they were donated to me, so I worked with what I had. Regardless, hopefully they stand a chance to colonize.
This chart, taken from North Spore, provides a broad range of tree species substrates and their compatibility level with various fungi.
For log freshness, it’s ideal to inoculate it within the first two weeks after cutting it. Only harvest healthy, disease-free logs for inoculating, and avoid using logs with damaged bark. The longest possible time you should wait to inoculate your logs is four weeks. After that, the likelihood of your logs becoming contaminated with other fungi greatly increases.
For log size, choose logs that are 3″-8″ in diameter. For drilling methods, a 4-6″ diameter is perfect cut at lengths of 3-4′. Any length is OK, but 3-4′ is great for storing and stacking on pallets. Also, keep in mind that the bigger the log, the heavier it is. I have received some sustainably harvested logs that were some 12″ or more in diameter, 4 feet long. Let me tell you, handling logs that big is an accident waiting to happen. Thus, I don’t recommend it unless it’s a healthy tree that needs to be cut for land management, and you’re inoculating it without moving it hardly anywhere. In conclusion, choose a log size that matches your strength.
What Time of Year Should You Cut Your Logs?
Although you can cut healthy trees to make mushroom logs most of the year, some times are better than others. The worst time to cut logs is in spring between bud swell and full leaf out. During this time, the tree directs most of the nutrients toward flower and leaf production, away from the trunks and branches. Further, bark is more loose at this time, and intact bark is vital for spawn colonizing the log and the eventual fruiting.
Any other time of year is good for harvesting logs. However, the best times of the year for cutting logs is in fall when a third of the tree foliage has changed color until all leaves have dropped and in late winter to early spring before bud swell and leaf out. During these times, trees will store sugary sap in the wood, making nutrients more available for spawn colonization. Additionally, the bark stays tightly attached to the tree at these times.
How to Inoculate Your Log with Your Shiitake Plug Spawn
For 100 spawn plugs, the number of logs you’ll need will depend on the size of your logs. You will want 1-4 logs, four logs if the logs are small in diameter, and one log if you have an 8″ diameter log or larger (if you’re feeling strong!).
So now that you’ve got your logs, a little bench, your electric drill, a crock pot with melted wax, maybe a ruler, and perhaps a hot beverage and some snacks…I’d say we’re ready to go, right?
First, using your 5/16″ bit, drill 1″ deep holes 4″ to 6″ inches apart. Drill each new row of holes 2″ apart from existing rows, and stagger the holes row to row in a diamond pattern. Do not drill holes into the cut ends of the log. When deciding on the spacing of holes, always consider how many spawn plugs you have. Although you do not yield larger harvests by drilling and inoculating more holes, the fungus colonizes the log faster the closer the holes are spaced. If you space the holes too far apart (farther than 4-6″), you risk fungal competitors colonizing that precious space. If you have a limited number of spawn plugs, closely estimate the minimum number of plugs you’ll need for each log. The last thing you need is to ruin your efforts by drilling to many holes and running out of your spawn plugs!
Now that you have your holes all drilled, it’s time to inoculate the logs with your shiitake plug spawn. In general, it works best to use a mallet to hammer in you spawn plugs. Make sure you hammer in your shiitake spawn plugs until they are level with the bark.
Once you’ve hammered in some or all of your shiitake spawn plugs, you can cover each hole with melted paraffin or beeswax. If you go an alternate route from buying this shiitake grow kit, I highly recommend investing in a wax dauber (see image below). They are super cheap and there isn’t anything you’ll have at home that will work quite as well to sponge up and spread your wax. This will spread the hot wax nice and thin and it will be less prone to cracking off your logs.
Now, you’re almost done with your log project to grow shiitake mushrooms. Seal one or both ends of your log with hot wax. If sealing one end, the idea is to leave one end open to soak up rain and moisture while the other sealed end helps retain that moisture. Moisture will still enter through the bark if you decide to seal both ends. I have tried using a paint brush to seal the ends, but extra wax solidifies in the brush, making it difficult to apply smooth hot wax. Thus, I have had tremendous success using my wax dauber to seal the log end. It may be a much smaller tool, but it goes faster and works better because of its effectiveness.
Stack your wood low to the ground on a pallet or pieces of scrap wood so they are not directly touching the forest floor. Store your logs in the woods or a shady part of your garden. Once they’re colonized, arrange the logs in a log cabin style for good airflow and harvesting your shiitake mushrooms. Colonization takes about six to twelve months, depending on the kind of wood, temperature, and how closely spaced the spawn holes are. When inspecting your logs periodically, if the wax sealing falls off or cracks, do not worry. The mycelium only needs a few weeks of protection after you’ve inoculated the logs.
If you’re interested in other articles about growing fungi, check out my other blog articles here!
References
- North Spore. 2023. Plug spawn inoculation methods. https://northspore.com/pages/plug-spawn-inoculation-methods?_pos=12&_sid=62097361c&_ss=r
- North Spore. 2023. Sawdust spawn inoculation methods. https://northspore.com/pages/inoculation-methods?_pos=18&_sid=62097361c&_ss=r
- North Spore. 2023. How to grow mushrooms on logs, totems & stumps. https://northspore.com/pages/grow-mushrooms-on-logs-videos
- Cotter, T. (2014). Organic Mushroom Farming and Mycoremediation: Simple to Advanced and Experimental Techniques for Indoor and Outdoor Cultivation. (1st ed.). Chelsea Green Publishing.