For some reason experimenting with mushroom cultivation was something we (especially Erkki) wanted to do in our permaculture project. The main idea was to develop a kind of low-tech mushroom cultivation system following the lines of traditional Japanese outdoor shiitake cultivation. On the other hand the idea of just buying the inoculation material wasn’t satisfying so also growing the mycelium ourselves was a key idea.
There are several sources of information which are listed in the end of this article. While reading bear in mind that this story is just starting – so far we have seen one oyster mushroom outside late last fall and a few shiitake in the inoculation bags I have grown this spring. So there is no guarantee that following the methods described here will result in any number of mushroom. But we definitely hope they will.
There is a lot to say about mushroom or fungi in general and their importance for the health of ecosystems. Search for ”Myco remediation” and you’ll get an idea of the discussion that is evolving.
For the purpose of mushroom cultivation and understanding fungi in your permaculture system (or any system) you should at least know that fungi can be symbiotic with plants (mychorrizal), saprophytic or parasitic. Mycorrizal fungi are vital to almost all plants and many of the edible mushrooms we pick in forests are mycorrizal. So if you are farming or gardening you should be aware of this and the interaction between plants and mycorrizal fungi and how to enhance that interaction. On the other hand these mushrooms are very difficult to cultivate as they form such complex interactions with plants and bacteria which are not fully understood.
Saprophytic fungi are unique creatures in the ecosystem because they can break down lignin. Without them dead wood would just keep piling up. Incidentally that’s what happened when oil and coal were formed – no saprophytic mushroom yet at that time geo-biological history. Many mushrooms we pick in the forest are saprophytic and most mushrooms we cultivate are. Saprophytic fungi can be primary decomposers which decompose wood or secondary decomposers that require that primary decomposers have already started to chew the wood first. The most commonly cultivated mushrooms are the Portobello type (Agaricus sp) which are secondary decomposers while the main topic in this article are primary decomposers like Shiitake, Oyster Mushroom etc.
Parasitic fungi is the type you normally are not so fond of – f.ex. most plant or forest diseases. But some are medicinal like the famous Chaga (Inonotus obliquus – pakurikääpä in Finnish) and might therefore be cultivated.
So where do you start? You can think of mushroom spores as seeds – so that is where the genetics of the mushroom are rearranged, and mycelium as the vegetative part of the mushroom which you can clone. Somebody somewhere chose a specific mushroom for good taste, appearance, productivity or some other reason and cloned it. Basically you need to get a pure sterile piece of mycelium on a sterile agar petri plate and take it from there. Or – more easy – you could buy a pure culture from a commercial supplier. Or you could use any mycelium culture that is available. The main point to think about though is that the vitality of the mycelium decreases with every generation step. At some point you need to go back to the spores.
The main reason to grow the mycelium is to multiply it before using it for inoculation. So you go from agar plate to grain spawn to saw-dust spawn -multiplying each time by the factor of 5-20. Sawdust spawn is what you finally use for inoculating the growth media, f.ex. logs.
The easiest thing to do of course is to buy sawdust spawn from a commercial supplier. But you could save a lot of money without much trouble by buying grain spawn and growing your own sawdust spawn inoculating the sawdust with grain spawn. And at least for me it is more interesting to control and understand the whole process. I am not giving all the details here because you can find loads of information about this on the internet or by reading Paul Stamets book listed below. But it is not too difficult, you can do it at home and all you need is to build a glove-box and buy a pressure cooker to get started.
Shiitake cultivation in the Far-East has been going on for more than 1000 years. However until the early 20th century it was based on creating circumstances where the logs would be naturally infected by Shiitake mushroom – and logs infected by something else would be discarded of. So cultivation based on inoculation of logs with pure mycelium is a relatively recent innovation. And of course most of the Shiitake on the market is produced on other substrates in controlled indoor conditions – not on logs anymore at all (but that’s an other story).
Below I describe outdoor production of Shiitake based on how I understand it so far and what we have done (again: not a single Shiitake produced so far). Other primary decomposers can be cultivated more or less in a similar way as I explain further down.
- Logs. If you are a forest owner you can probably get the logs from your own forest – otherwise you need to buy them. You’ll be felling the trees and cutting the logs in the late winter as close as possible to the time of inoculating them. In any case between the falling of leaves and development of buds. The warmer the winters in your climate, the higher the risk of the logs being infected by natural fungi.
- Oak is considered the best tree for Shiitake cultivation but other deciduous (hard wood) species should do as well; f.ex. we are inoculating birch and alder.
- The logs should be approximately 1 meter long for practical purposes and 7-20 cm in width. You’ll be lifting the logs even when they are wet so a 20 cm thick log will be pretty heavy.
- After felling the trees you should protect the logs from drying and mould (keep them moist inside – dry outside). A loose pile under the canopy of a fir forest is suggested.
- The two main methods of inoculating the logs are sawdust spawn and wood dowels. In either case you drill holes in the log and fill it with spawn or the dowel and cover the whole with wax. We are using sawdust spawn and beeswax. The latest method is sawdust plugs with wax cover ready on the plug. Many suppliers have certified organic spawn.
- For drilling we are using a grinder with an adapter for a 12 mm drill-bit. I bought the adapter and grill-bit at Field&Forest in the USA. I haven’t seen this kind of setup in Europe. The problem is that you also need the grinder from the USA as the adapter is not metric. The advantage compared to a normal drill is speed (10000 rpm) and because of the high speed the drill-bit sterilises the holes. As we are not connected to the grid we are using a cordless grinder.
- I also bought the inoculation tools from Field&Forest. If you don’t have inoculation tools it is better to use wooden dowels. However using sawdust spawn is said to be more economical and effective.
- As we also have bees it seems natural to use beeswax – although as we just started with bees last year we don’t have beeswax from our own bees yet (we will this spring). You could also use f.ex. cheese wax – any way the wax should be food quality and if you are producing organic the wax should also be certified organic.
- If you are using several different strains of mushroom you better think of a way of labelling the logs. We are labelling with tree species, month of felling the tree, mushroom species and strain and date of inoculation. We are using metal labels and a permanent marker hoping they might still be readable after a few years (?). We are cutting pieces from used venetian blinds and using a staple gun.
- You can hope to harvest the following year but the highest productivity should be in the year after that. Real slow food! Now the main task is to keep the moisture level inside the logs sufficiently high at minimum 30%. So keep the logs protected from sun and wind summer and winter. An old-growth fir forest should do fine – and we happen to have that. We put the logs in one layer off the ground so they catch rain well but are not directly on the wet ground. In the winter they should be covered with snow.
- For production the position will be changed and there are several options. The right one depends on where you are.
- According to American sources you can expect up to 1,5 kg fresh mushroom per log over its 3-4 years of production. Growing Shiitake involves a technique called ”forcing” which involves soaking the logs in cold water. Forcing enables the grower to control the production rhythm of the mushroom which is necessary especially in commercial cultivation. However it is a lot of work.
There are other primary decomposer mushrooms you can cultivate similarly to Shiitake. Last spring we inoculated 8 different strains of Shiitake which are Wide Range (WR), Warm Weather (WW) or Cold Weather (CW). Having different types of strains should help spread out the production over the growing season. We are also testing different Oysters, Reishi and also two domestic mushrooms: Kuehneromyces mutabilis, Sheathed Woodtuft (koivunkantosieni in Finnish) and Hypholoma capnoides (kuusilahokka in Finnish). Especially Sheathed Woodtuft has been experimented with in Finland for years as a potential cultivated mushroom. I am getting strains of both species thanks to Jouni Issakainen who is researching mushroom cultivation at the University of Turku.
All in all we inoculated some 300 logs last spring and are hoping to see a few mushrooms this year. This spring we will inoculate an other 300.
Some sources of information I have found useful:
On the internet:
Field & Forest (USA)
There is a lot more out there. Just search the internet.