How to Cultivate Mushroom Spawn: Steps for Grain & Plug Cultivation

How to Cultivate Mushroom Spawn: Steps for Grain & Plug Cultivation

If you are interested in how to cultivate mushroom spawn with grain substrate or plugs, then this article is for you

Growing mushroom spawn is a fun aspect of mushroom cultivation. By growing spawn in-house, growers can start to experiment with new strains and build a whole new skill set. When bringing spawn in house it also adds a whole new set of problems to worry about and troubleshoot.

In this post I describe how to cultivate mushroom spawn and some situations that work and don't work for growing your own spawn. At the bottom is how to inoculate plug spawn, which is much easier than growing spawn. Don't get intimidated by the description of how to cultivate spawn using grain, because growing on dowels is EASY!

How to cultivate mushroom spawn step-by-step using grain

  1. Mix substrate. For substrate we use 1 part water, 1 part grain and 1/5 vermiculite. This works out to about 1000 grams of water, 1000 grams of grain (oat is what we have used lately but, wheat, rye, millet all work) and 200 grams of vermiculite. This is layered in the bag grain, vermiculite, and finally water. 
  2. Fold bags. This simple step can be the difference between success and failure. Bags that are not folded properly can be extremely difficult to seal, taking longer to do and sometimes not sealing at all. Bags should not have any creases in them or any substrate in the area that is going to be sealed. You have to be extremely picky if you want to cultivate mushroom spawn properly.
  3. Load pressure cooker. When loading an all American pressure cooker we typically will load the first bag against the column, which will be the last bag to come out. With a 41 quart sterilizer we do two layers of 5 pound bags. Each layer has 3 bags. The first bag on the top layer is in the space between the handles. With this orientation bags can be pulled out without ripping the sides.
  4. Inoculate. Inoculation should happen in front of a flow hood. Grain spawn is high in nutrients so can contaminate easily.
  5. Incubate. Once inoculated, bags should be kept between 60-75 degrees Fahrenheit during incubation. Spawn typically takes about 2-3 weeks to colonize.

When to cultivate mushroom spawn

Cultivating mushroom spawn is great, I think, in several cases:

  • If you are a hobby grower and want experience in all aspects of cultivation.
  • If you are growing strains or species that are not available through other spawn providers.
  • If you are a commercial grower who has a firm grasp on both fruiting and block production and you have a dedicated person to focus on spawn production.

How to cultivate mushroom spawn and why cultivate mushroom spawn are closely linked. I would not recommend growers starting out to produce their own spawn and I would not recommend most hobby growers to grow their own. Spawn is really an aspect of the mushroom cultivation industry that can stand separate from block production and fruiting of mushrooms.

How to cultivate mushroom spawn-using plug spawn

Cultivating mushroom plug spawn is much easier than grain spawn. This process does not require a pressure cooker or flow hood. Since plug spawn is much lower in nutrients it is harder to get contaminated. This method makes it easy to go from one 5-pound bag of spawn, which is $28, to over 10,000 plugs, a value of over $300!

  1. Start out with high-quality spawn purchased from Fungi Ally and filter patch bags or gallon ziplock bags.
  2. Boil plugs for about 1 hour, drain the water off and allow to cool.
  3. Be sure all excess water has drained off and place plugs in filter patch bags if you have a sealer or regular ziplock bags. Leave enough room that the bags can be easily shaken to distribute the spawn.
  4. Add about 2 cups of spawn into the plugs. Seal the bags either by using the ziplock or sealing the bag.
  5. Incubate the plugs in the dark at a temperature around 50-60 degrees. This works great for both shiitake and oyster mushrooms!
  6. After about 3-4 weeks the plug spawn will be colonized and ready to use for inoculating logs!

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