• Tom Brain

Using Grain Spawn

Updated: Aug 23, 2019

Grain spawn can be a challenge to use for the beginner mushroom cultivator, but the challenges can be worth it.

If you purchased grain spawn through Oak and Spore, it will come in a sealed bag that has a filter path. This bag has been sterilised and contains mushroom mycelium growing on moist grain. This grain will be ready to use to inoculate the substrate of choosing, whether it be in bags, buckets, beds, or monotubs!

Grain spawn is a highly nutritious substance, and because of that the mycelium can quickly form a dense white coating over the top. If this happens you can break the mushroom spawn back up into grain sized pieces with your hands. Do not open the bag to do this! Our goal is to make it easy to spread the spawn while keeping it sterile.

Once the spawn is broken up we want to ensure the bag is clean right before we open it. To do this we spray and wipe it down with isopropyl alcohol. This will prevent any competing organisms that are on the outside of the bag from ingressing into the spawn. And remember to wear gloves cleaned with isopropyl alcohol as well!

grain spawn
Grain spawn that's infected with mycelium - Oak and Spore


One of the easiest ways to start growing mushrooms is to make a mushroom totem in your backyard. This is done by spreading the grain spawn out between some layers of fresh cut tree branches or stumps. With the spawn sandwiched between the cut faces of the wood, it quickly infects the wood and can produce mushrooms for years to come! Checkout out mushroom totem guide on this website.


If you have decided to grow in sterile bags, you will need to ensure the substrate has been sterilized, and you have a laminar flow hood to work in front of, and an impulse sealer to seal the bags. You can use a cable ties with cotton, but chances of contamination are very high.

Once the bags have been sterilized, simply use a sterile metal spoon to scoop the grain spawn into the bags, then impulse seal them shut. After they are sealed, you can shake up the bag and distribute the grain evenly around.

This will ensure the fastest time for colonisation of the substrate.


If you have decided to grow in buckets with straw, we will assume you have pasteurized

or used the lime sterilisation technique to clean the competing organisms off the straw.

Simply open the bag and tip the spawn into the bucket. Replace the lid and give a shake to distribute it.

Mushroom Beds Some people choose to grow in mushroom beds; King Stropharia, Shaggy Inks, and Morels are great for this. It is the easiest as you are not really worrying about being too sterile. Once your bed is prepared, simply open the bag and spread out the spawn through the garden bed.


Monotubs generally rely on pasteurization to clean the substrate. Once pasteurization is complete, open the spawn bag, and tip through the substrate. With a sterilized metal spoon, spread the spawn through the substrate.

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