Mushroom Madness Part 4: Experimental Techniques
Welcome back to our fourth and final (?) installment of Mushroom Madness! In this episode, we will be talking about some more experimental mushroom cultivation techniques. These are less proven and not guaranteed to produce mushrooms, but they are guaranteed to produce knowledge! And isn’t that what life is really about?
If you haven’t yet, please take some time to check out our YouTube Channel and this video we made about experimental mushroom tek.
This essay will be broken down into three sections:
“Passive” cultivation techniques. These are techniques that are focused on increasing the proportion of fungi in the environment without actively culturing mycelium.
“Active” cultivation techniques. These involve more deliberate cultivation of fungal mycelium, but still in non-sterile environments.
Other experimental uses for fungi. Here we will explore things like pest control, mycoremediation, and more!
Let’s start with the passive technique. The general philosophy here is to create environments that fungi can thrive in and then gently nudge them in the direction of more fungi. To me, this seems like the most sustainable option long-term, and is the direction that I believe we should be moving towards. It has the lowest energy requirements and is the most holistic in its approach.
That being said, it is not possible everywhere yet, and so more intensive cultivation techniques, including sterile culture techniques, can be useful levers for moving us in the direction of long-term “passive” cultivation systems. I put “passive” in “quotes” because, as you’ll soon see, it actually does require quite a bit of intention.
The first point I want to make might seem obvious, but apparently it still needs making. Many of the fungi that we like to eat live in the woods. Any amateur mushroom hunter can tell you that! So with that being said, if we want there to be more edible and medicinal mushrooms around, our best bet is to simply PLANT MORE TREES! By simply creating the space for the mushrooms to grow, spores blowing in with the wind or on the foot of a bird or squirrel will find their new home in the trees that you planted and will begin to grow.
Right: Oyster mushrooms in their natural habitat: a tree
“Many of the fungi that we like to eat live in the woods. If we want there to be more mushrooms around, our best bet is to simply PLANT MORE TREES!”
Nuts and Bolts Nursery offers many types of mushroom-friendly trees, like Oaks and Hickories, in our store. By planting them and encouraging your friends and family to plant them as well, you are helping to increase the prevalence of edible and medicinal mushrooms!
Beyond planting trees, the next step up in “passive” cultivation is to make yourself a human spore-print. Whenever you see a wild fruiting mushroom, cover yourself in the spores! Rub them on your clothes, in your hair, on the bottoms of your boots- everywhere! As you walk around, the spores will slowly fall off into your surroundings. Then, especially if you are planting trees in your path too, mushrooms will follow you around everywhere you go!
“Cover yourself in the spores! Rub them on your clothes, in your hair, on the bottoms of your boots- everywhere!”
Left: Andy puffing puffball mushroom spores onto their jeans.
When harvesting wild mushrooms, it is always good to leave at least a little piece of each flush intact so that it can sporulate into the wind and produce more mushrooms for years to come.
Next we have in-situ culture transplants. This is where we take a piece of mycelium from one location where we find it growing (this could be wild or from the lab) and relocate a piece of it to another location from which we wish to harvest. Perhaps we recently cut a tree and now there is a fresh stump. An oyster mushroom fruits on a log in the woods, and we grab a small piece of the white mycelium-inoculated rotting pulp and stuff it into a crack in the stump. If we’re lucky, the transplant will take and now the stump becomes a small mushroom farm!
This last technique brings us nicely into the realm of “active” non-sterile cultivation techniques. What makes these techniques “active” is that they involve the culturing of actively growing mycelium in a controlled (but not sterile!) environment.
The first active technique I’d like to talk about is cloning. Cloning is asexual reproduction (as we covered in Episode 2: the Live of a Fungi) and is very easy to do with fungi. Sterile culture technique is to cut open a mushroom inside a glovebox or fume hood, extract a small piece of interior flesh, and transfer it to a sterile agar plate. Agar plates are extremely nutrient rich, and thus easily contaminated, so sterility is a must, they say. But I say NAY!
Taking transfers of mushroom tissue can be done under highly non-sterile conditions by taking them to cardboard instead of agar. The cardboard has little free nutrients for molds and bacteria, but the wood-loving fungi like oysters and shiitakes have no trouble digesting the fibrous delight! Simply take a piece of mushroom, the fresher the better, and smush it into the corrugations of some moistened cardboard. Place it in a bag or tub to retain humidity and let it grow! Contamination is almost certain to occur, as the mushroom itself is highly nutritive and covered in contaminant spores, but the un-contaminated regions can then be periodically cut away from the contamination and transferred to clean cardboard, as shown below.
Once you have a relatively clean culture growing on some cardboard, you can gradually layer it with more cardboard strips to expand your spawn. Once you have enough, you can wrap freshly cut logs in the cardboard spawn to inoculate them. Keep it moist by wrapping the cardboard in some scrap plastic until the mycelium has successfully moved into the log. Once the log is fully colonized, mushrooms will start popping out of it! You can cover yourself in the spores and take further clones onto new cardboard to start it again!
“Wrap freshly cut logs in the cardboard spawn to inoculate them”
Cloning is great, but it can only go so far. Eventually the culture will senesce, or lose its vitality. Alternating between different substrates (types of wood, straw, other debris, etc.) can extend the life, but senescence is inevitable. To get around this problem, we have to start new generations from spores periodically. Spore culturing is notoriously the most sterile of the sterile culture technique, but can it be done under non-sterile environments? I say yes!
I like to take spore prints on cardboard and then simply moisten the cardboard in a covered petri dish to get the spores to germinate. While I have only successfully done this once with oyster mushrooms, and have since been unable to replicate the results, I know that it’s possible and am working on the best methods to induce germination of the spores. With spores germinated directly onto cardboard, we can simply expand the cardboard spawn and then wrap logs in it to produce fruiting spawn. This is still a highly experimental tek, so please join me in these experiments and share your data in the comments below!
“I like to take spore prints on cardboard and then simply moisten the cardboard in a covered petri dish to get the spores to germinate. This is still a highly experimental tek!”
Over multiple generations, we should be able to breed strains of fungi that are highly conducive to these non-sterile cultivation techniques. Spores that germinate more readily and mycelium that produces more antimicrobial molecules to protect it from contamination.
Generation of sterile culturing has bred fungi that produce high yields under sterile conditions, but it has likely bred out many of the traits that help protect fungi from contamination. In a sense, we have bred fungi that are dependent on our energy-intense sterility, and would be less able to naturalize in the environment. My personal breeding work focuses on regaining those fitness traits and improving the fungus’ ability to naturalize in a non-sterile environment. Won’t you join me in this worthy cause?
Finally, I’d like to just touch on a few of the other projects and experimental avenues that a pinning mycologist might explore.
The first is pest control. Insects can be a large problem in many agricultural settings. Particularly, I am interested in the chestnut weevil: a small flying insect that lays its eggs in the young chestnut and then eats its way out of the nut in the fall. Weevils can seriously compromise chestnut yields and render them unfit for long-term storage if not properly dealt with. Poultry under the trees is a great way to mitigate their damage, as the birds will scratch up the larva in the ground before they can reach adulthood, but one particular fungus intrigues me in its potential to help with this problem as well. That fungus is Cordyceps militaris.
There are actually many species of Cordyceps, and all of them might be potentially useful. They are all entomoparasitic fungi or fungi that attack insects! They can mummify the insect and turn them into a mushroom. Some even hijack the motor nervous system of the insects, driving them to high places or into the heart of the colony so that the ensuing mushroom can spread its spores to the maximum number of new subjects. How cool!
I hope to train Cordyceps fungi to parasitize weevils to improve nut production systems. Cordyceps mushrooms are also highly nutritious and medicinal!
Above: Orange Cordyceps militaris mushrooms beginning to show tiny pins on a supplemented rice substrate.
Lastly, much research has been done lately into the field of mycoremediation, or the use of fungi to clean up contaminants. We touched on this earlier in the series, but fungi can chelate heavy metals and digest petroleum products, helping to clean up toxic industrial waste. Currently I don’t have any active experiments going, though I do hope to train some oyster mushrooms to eat various types of plastics. One day.
If you’ve got any experiments going, post about them in the comments; we’d love to connect about them!
Questions about any of this, don’t hesitate to ask! The whole point of this post series is to get more people thinking and doing mushroom cultivation in a more sustainable and holistic way. Information is the critical resource! Let’s share it!
That’s all for now! Hope you found this interesting and helpful.
Mush Love,
Andy and Nuts & Bolts Nursery Co-Op
