Updated: Dec 21, 2021
Mushrooms are often looked at as plants, so naturally people think you can simply get some mushroom spores and grow some more mushrooms - just like getting a seed from a plant and growing it. Unfortunately, with fungi, it is not that simple - although there are some simple options.
This post will go over the full life-cycle of a mushroom. This will help you understand the pros and cons of trying to grow your own mushrooms from spores, from pure agar-culture, from liquid-culture, from grain-spawn or via the simplest option: from mushroom grow-kits. Read on to decide which option suits you best.
The Mushroom Life Cycle
The lifecycle of a mushroom is very simple in the wild: a mushroom fruit-body rapidly grows, ripens, releases billions of spores, rots and dies. But bear in mind that usually only the mushroom fruit-body will rot and die.
The actual organism -- the mycelium mat -- is mostly unseen underground. This organism will continue to live and produce more future mushrooms & spores.
The mushroom we see is comparable to only seeing the flower on a rose-plant. The mycelium being the remaining bulk of the plant, unseen, underground: the flower blooms and dies, but the rose-bush itself continues on to flower many more times. The mycelium mat will continue to live on and grow -- if conditions are good and there is plenty of food to consume.
One of the oldest living organisms on earth is a giant mycelium network located in the Western United States. This example of Armillaria Ostoyae, also know as the Honey Mushroom, covers some 2400 acres of land, weighs approximately 35,000 tonnes, and is estimated to be between 2500-8000 years old - making it the probable oldest single living organism on earth and one of the largest.
Mushrooms release spores in bulk, dropping billions to even trillions. Only a very very small amount of spores will actually go on to germinate, mate and grow into mycelium to produce mushrooms. Some spores may even make it to growing mycelium but that strain (genetic variant) of mycelium may not be able to produce a mushroom fruit body to reproduce.
For this reason mushroom farms will often use known/ bred or wild-cloned commercial cultures, with desired traits, to produce high quality mushrooms with aggressive growth, good yield and flavour profiles.
If some spores make it to a location with favourable conditions -- usually warm, moist, and with a good food source -- the spores will germinate like a seed. Mating will take place and mycelium will begin to grow.
Mycelium will begin to rapidly grow through the food source seeking out food, water and other nutrients. The mushroom will try to gain as much mycelial mass as it can. Once a desirable amount of food is obtained - and environmental conditions are right - the mushroom fruit-body formation process will begin. In the mushroom growing process we refer to this mycelia growth as the incubation period: this can be anywhere from 7 days to 12+ months and is usually done by expanding mycelium from grain-spawn through a nutrient-rich food source we make.
Fruit Body Development:
Once favourable fruiting conditions are met (usually good temperature and high humidity), the mushroom/mycelium will begin the fruiting process. This can look different depending on the species, but generally the mycelium will form primordia.
Primordia are essentially baby mushrooms. Often hundreds or even thousands of primordia will form initially. However, only primordia in the most likely positions to spread spores will be naturally-selected to develop. These lucky ones are directed food and resources to develop into a healthy mushroom. The mushroom fruit-body is actually just condensed mycelium. With farming mushrooms this process can be influenced by the unique genetics and traits of each strain, some are better than others for cultivation because of this, so selected cultures are used.
Mushroom Fruit Body Maturity: (The cycle begins again)
Once the fruit body has reached full maturity microscopic mushroom spores will begin to release into the air, from the gills, and spread to new locations anew.
Oyster mushrooms, which are commonly cultivated globally, are known for their high spore load. Commercial strains of oyster mushrooms are bred to have reduced spore loads, making them safer and easier to cultivate indoors.
The NZ Native Oyster (Velvet Oyster) is a great example of this, an excellent eating mushroom that's beautiful to grow, but difficult to manage in indoor fruiting environments due to its massive spore load. When regularly dealing with large amounts of oyster mushrooms, respiratory protection should be worn while in the fruiting chamber, and exhaust fans need to be cleaned regularly.
We have some amazing medicinal NZ native mushroom cultures to cultivate such as the Velvet Oyster (Pleurotus Parsonsiae), Tawaka/ Poplar Mushroom (Cyclocybe Parasitica), Turkey Tail (Trametes Versicolor) and our own Native Lions Mane (Hericium Novae-Zelandiae).
Since NZ has very strict biosecurity laws and importation of mushroom cultures is heavily restricted, most of the native mushroom cultures have been collected by cloning wild mushrooms or germinating spores on agar in the lab. These are then grown out in to many different strains to find one we like. This process takes considerable time but is worth it in the end -- once a good culture is found it can be kept in long-term storage on culture slants and propagated for many many years.
We are also lucky to have some good commercial Shiitake, Grey Oyster, Enoki and Button/ Portobello strains that preform very well: these strains have been imported from global culture banks.
The Big Question: Spawn or Spores?
This is a common question we get: "How to grow mushroom from spores?"
Growing mushrooms from spores requires some specialised lab-equipment such as agar plates and a laminar flow hood, good knowledge of sterile technique and strain-sector identification from the agar. For the average grower this is a lot of work and will often fail or end in undesirable results.
So the solution is grain spawn. Mushroom grain spawn is a mix of sterilised grains with your desired mushroom mycelium grown through it. It is hungry and ready for more food and eager to produce a mushroom. This, for most people, is the best way to expand mycelium and grow mushrooms at home -- you know exactly what you are getting and that the mycelium will fruit desirable mushrooms. The grain also acts as little nutrient power packs for the mycelium to grow thick and strong!
We have our 5 Step Oyster Mushroom Grow Kit which teaches you how to use grain spawn & mix up and pasteurise bulk substrate to grow mushrooms at home. The kit is designed to be scalable so you can grow as much or as little as you like anywhere from small hobby grower up to a market supplier. I can supply weekly commercial grain spawn for those that would like to produce mushroom for their local community or market. Feel free to give me an email to discuss.
If you would like to get a little more involved then you can move up a level and have a go at inoculating some sterile grain with liquid culture. Liquid culture is simply a nutrient liquid with pure mycelium grown through it, it is then injected into the sterile grain bag for the mycelium to grow and turn into grain spawn.
The most advanced way to grow out mushrooms is germinating spores on agar plates. If successful you will get mushroom mycelium growing on the agar. This mycelium can either be sectored out into each strain on the plate or transferred onto grain to let them fight it out. I won't go into the full details of how this is done in this post -- there is good info with some googling on how to sector strains from spores etc.
Alternatively you can buy a known quality culture and use that to grow more mycelium on agar plates and then eventually onto grain spawn. To do any of this reliably you would ideally need a laminar flow hood to avoid contamination of the cultures.
To summarise I personally think for most people you are best to start with a simple mushroom grow kit -- get an understanding of the life cycle and stages of growth with the kit, then try having a go using spawn using your own substrates. Starting with an oyster mushrooms kit is by far the easiest and most reliable way to get into indoor mushroom growing. Next easiest is setting up outdoor patches and mushroom logs for outdoor mushroom cultivation.