North Spore – BULK – Sterilized Grain Bag

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PRICE: $158.40

Accelerate and maximize your mushroom grow with North Spore Sterilized Grain Bag. Full of nutrient-rich millet and wheat berries, the grain bag is an ideal environment for colonizing your mycelial spawn, and features a self-healing injection port for contamination free inoculation.


Free shipping available for orders $100 or more. Manufacturer Direct and special order items may require extra charges. See the Docs & Downloads section for product labels and other important information. Questions? Contact us!

Product Features List
  • Specially formulated mix of millet grain and wheat berries
  • Ideal environment for mycelial colonization
  • Self-healing injection port for spore syringe inoculation
  • 0.2 micron filter patch for contamination-free gas exchange
  • Professionally sterilized to reduce contamination risk
  • 8-pack



North Spore’s organic sterilized grain spawn bag was formulated by mycologists to maximize the speed and size of your mushroom grow. (All that’s required is a spore syringe or liquid culture!)

Each spawn bag contains a proprietary grain blend featuring hydrated, nutrient-rich, organic millet and wheat berries. Bags also include a self-healing injection port for use with a spore or culture syringe plus a 0.2 micron filter patch for contaminant-free gas exchange Note: Color of injection port may vary.


Please select a variation to see its technical specifications



To inoculate the grain bag, inject your spore or culture syringe through the port in a sterile location. Use clean hands and latex or nitrile gloves to reduce the introduction of contaminants.

It is best practice to wait a minimum of 1 week after arrival before injecting grain bags to ensure they were not compromised during transit.

Recommended ratio is 2.5-5ccs per 3lb injection port bag. Typically, it is not recommended to use an entire syringe in one bag. Doing so adds excessive moisture which can create over saturation in the bag. This over-saturation can pool and is prone to being anaerobic, making it more difficult for mycelium to colonize.



Allow your bag to colonize in a cool location out of direct sunlight. Temperature for incubation shouldn’t exceed 75 degrees F or dip below 55 degrees F. After a couple of weeks, you should start to see mycelium growing on the grain. 

You’ll notice the white mycelium growing outward from the injection point. When it has grown three to four inches you should, without opening the bag, carefully break up the colonized grain and mix it into the uncolonized grain. This will dramatically speed up the colonization process.

When the bag is completely white with mycelium your spawn is ready to use. This may take a couple of weeks to a month or more depending on the species and vigor of your culture.

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