Presentation on theme: "Small Scale Mushroom Cultivation. History Mushrooms have been revered for thousands of years in cultures around the world for their edible and medicinal."— Presentation transcript:
History Mushrooms have been revered for thousands of years in cultures around the world for their edible and medicinal properties. Though cultivation outside of their native habitat is a fairly recent development. There is historical evidence of mushrooms in cultures across the world including Rome, Egypt, Aztec and South American cultures. Cultivation began in France in 1650 when a melon farmer discovered volunteer button mushrooms on his manure pile and decided to relocate and ultimately propagate them.
Nutrition Not only are mushrooms high in B/D vitamins and trace minerals, but they have proven to have antimicrobial properties and have been shown to significantly aid the immune system. They also assimilate into the system quite well as fungi is so closely related to animal species. Medicinally, several varieties have been trialed in cancer treatments and proven to retard tumor growth and the effects of radiation treatment. Penicillin, streptomycin, and tetracycline are all fungal extracts.
Fungi Mushrooms are saprophytes, meaning that they feed and thrive on decomposition. That’s why we tend to find them on fallen logs, compost piles, the forest floor, etc. They colonize the decomposing material, otherwise known as substrate, in a similar way to root systems, but instead a branching set of hyphae called mycelium. Mycelium holds the record as the largest living organism recorded. From the mycelial network emerges the fruiting mushroom. The fruit grows to maturity and then releases its airborne seeds called spores. The few spores that land on arable land and survive begin to colonize and repeat the process.
Sterile Culture Transfer To successfully propagate mushrooms, the first step is to collect a sterile tissue sample. With this sample we will contain the spores of the mushroom to a sterile medium that can be stored and used to inoculate grain in the next step of the process. Though there is fancier tech available, glove boxes provide a sterile environment with visible access to make home culturing more plausible. Though it is sometimes best to trust the mycologists, for sake of consistent results.
Agar Culture Agar is a starch based medium that effectively cultures and stores the tissue sample. It is an ideal environment for spores to flourish and offers a plentiful food supply. The two most common forms of agar used in mycology are potato dextrose agar (PDA) and malt dextrose agar(MDA). These are also used to propagate bacterial and viral cultures. It is essential to work with this in a totally sterile environment.
Grain Spawn Once you have created or procured your agar culture, the next step will be to inoculate some sort of finer substrate that than can then be used as spawn for logs/bales/etc. The grain used is generally either wild bird seed, rye seed, or grass seed. The grain is put into a sterile bottle or jar and is then pasteurized in a pressure cooker. Once pasteurized, it is then left to cool, as not to cook the agar culture. Once cool it is inoculated with the agar culture. The grain is then kept covered at a fixed humidity and a comfortable temperature. In several weeks time the grain is fully colonized and you will see that the mycelium has enveloped the grain.
Substrate Being that mushrooms are saprophytic, they have a wide range of what can constitute their diet. In the natural world anything that offers decomposition, moisture, carbon dioxide, and carbon is a suitable environment. The time it takes to inoculate is directly based on the density of the substrate. For example, duff is going to take a lot less time to become fully inoculated than say a fallen log. Knowing and observing this, we can recreate the conditions of the natural world in the way that best suits our timeline.
Inoculation Methods of inoculation vary slightly between different types of substrate, but the basic principle is more or less the same. Break up the spawn, distribute it evenly throughout the pasteurized and reasonably moist substrate. From there it is mostly cut off from airflow and extreme temperatures so that humidity can build up and support the decomposition of the substrate. In our case with shitake logs, there are some finer points to include in the process.
Log Plugs First, we are ideally using fresh cut oak logs or some similar type of softwood, and looking for younger trees that have a lot of sapwood and not too much hardwood (the path of least resistance for the spawn). The ideal diameter is about 4 inches, but that’s flexible plus or minus an inch. We then cut them down to 40 inches and gave them an initial soak (optional). From there you are to drill 5/8x5/8 holes into the log at an 8 inch triangulated spacing, with the spacing a little heavier on the ends of the logs (usually a couple inches in for practicality’s sake). Once the holes were bored out, we then plugged them with the shitake mushroom spawn (you could alternatively hammer in compressed wood spawn plugs) and then sealed them with a warm mixture of paraffin wax and mineral oil. This ensures protection and seals in the moisture that the spawn requires. Once finished with this step we started our first soak. The logs like to stay relatively moist throughout their development, and under-watering them can lead to dormant or ineffective inoculation. The average rule of thumb is a 12 hour soak every 2 weeks, but that rate is obviously dependent on weather and the amount of evaporation occurring in the season (i.e. water more in the summer). Keeping the logs protected from extreme weather and loss of humidity, find a safe space for them in the winter and incorporate them into a shady grove in the summer.
Spawning Over the course of inoculation you will begin to see mycelium cover the ends of your logs. This is called the spawn run, and the mycelium is in the process of vegetating (rooting) and colonizing the substrate. Not until it is fully colonized will it be ready to go into fruiting. This can take up to a season depending on the substrate being used. In the case of logs, usually 9 to 12 months The closer we stay to the previously mentioned ideal conditions, the more of an opportunity the spawn will have to thrive.
Harvest The most rewarding stage of the process for most of us, we now get to reap what we have sown. Once we are getting towards comfortable fruiting conditions (spring + fall) and the spawn has successfully colonized, we can now prepare the logs for fruiting. A little more exposure and airflow, along with ample watering, will trigger the plants into wanting to produce their fruits and ultimately their spores for sake of survival. You will fist begin to see pinheads emerging sporadically, the initial formation or birth of the fruit. From there it will develop into a full fruiting body, usually gaining a bit of color as it comes into maturity. As you pick them in their prime, be sure not to disturb any of the newly developing pinheads. Harvest season varies based on species and substrate, but with shitake mushroom logs you can expect for the fruiting season to last for about 30-45 days. The log will then return to dormancy until the right conditions present themselves once again. The cycle continues
Maintenance Watering is the most critical point of mushroom production, as is the case with all living organisms. Consistent and mindful watering will reward you in the end. Second to that is a suitable environment for your spawn to flourish. Fungi love dimly lit, humid and temperate conditions. You can build such an environment yourself or find a just as accommodating niche naturally occurring somewhere on your property.
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