Preparing & Inoculating Grain Spawn

Part 2 : Unit 3 : Preparing and Inoculating Grain Spawn

This is the first proper meal you’ll be cooking for your mycelium – a hot, steamy mason jar with hydrated corn kernels inside. In this module you’ll learn to hydrate the corn, sterilize it in mason jars using a pressure cooker and then inoculate it with some liquid mycelium. If all goes well, the mycelium will slowly grow and spread in the jar. You can break up the grain and mix the contents of the jar once there’s been about 30% colonization. This spreads the mycelium around more evenly among the grain and gets the jar colonized quicker. Once the mycelium has fully spread, or “fully colonized the grain,” it will be ready for the next step: mixing it with bulk substrate. Let’s get ready to cook some delicious grub for our mycelial friends!

Colonizing jar of mycelium
Colonizing Jar Of Mycelium

Table of Contents - Preparing Grain Spawn

Preparing Grain Spawn in Mason Jars

Items needed
Notes & Tips

Video Tutorial : Hydrating and Sterilizing Grain Spawn in Mason Jars

The video markers above 👆🏼correspond to the the various Steps in this Unit. Click on them to skip to a Step.

Step 1 : Hydrate the Corn in Simmering Water for 3-4 Hours

You’re going to need an uninterrupted 4 hour block for this next step. Clean out the pressure cooker pot and add 4 lbs of dry corn kernels. Fill the pot half way with water and place on the stove. Turn on the heat to “high” and bring the water to a boil. Once boiled, turn down the gas to low so that the corn simmers in the water. Add water to the pot if needed, as water will evaporate and be absorbed by the corn. Keep simmering for about 3-4 hours, until the corn is well hydrated and can be crushed between your fingers. 

Step 2 : Dry out the Corn in a Sieve or Tray

Once the corn is ready, carefully pour it out into the sieve and drain out all the water. Allow the grain to steam off for about 30 minutes, occasionally mixing it around to expose underlying corn. Wait until the corn has no significant water on its surface before finally placing it in mason jars. You can use the “is the paper towel wet” test to see if the grain is dry enough or not. Dab a paper towel into the grain for a few seconds – if it has visible wet stains, it’s not ready yet and requires more drying. Don’t let your corn dry for more than several hours or else it will dehydrate.

Step 3 : Place Grain in Mason Jars and Pressure Cook for 90 Minutes at 15 PSI.

Once the grain is dry enough, put it in the mason jars, filling them about 3/4 of the way. You want to leave enough space in the jar to mix the grain later on. Make sure the silicone seal is in the lid and close the jar tightly. Cover the jar lid with aluminium foil. Proceed to  fill the rest of the jars in a similar fashion. Once done, place the 6-7 mason jars in the PC and pressure cook for 90 minutes at 15 PSI. Allow PC to cool off completely before opening.

Inoculating Grain Spawn with Liquid Culture

Items needed
Notes & Tips
Psilocybe cubensis mycelium colonizing grain spawn
Psilocybe Cubensis Mycelium Colonizing Grain Spawn

Video Tutorial : Inoculating Grain Spawn with Liquid Culture

The video markers above 👆🏼correspond to the the various Steps in this Unit. Click on them to skip to a Step.

Step 1 : Clean and Disinfect Everything

Wipe down and disinfect your workspace and mason jars. Remove the aluminium foil from the liquid culture jar and wipe down the injection port with alcohol. Do the same to two of the grain jars. You will be inoculating the grain jars in batches of two or three.

Step 2 : Unpack Sterile Syringe and Hypodermic Needle

Carefully unpack the sterile syringe and remove it from its package, without touching the syringe tip. Next, carefully remove the hypodermic needle from its wrapper and place it on the syringe tip firmly while still keeping the safety cap on.

Step 3 : Draw out 10 cc of Liquid Mycelium from the Liquid Culture Jar using the Syringe

Remove the safety cap from the syringe and insert the needle into the injection port on the LC jar. Tilt the jar slightly so that it’s facing downwards and the liquid mycelium reaches the inserted needle. Be careful while you tilt the jar – try to avoid getting the air filter inside the jar lid wet as it might bring on contamination of the LC jar itself. Once you can see some mycelium around the inserted needle, withdraw a few cubic centimeters (cc) of liquid.

Step 4 : Inject Liquid Mycelium into Grain Spawn Jar via the Injection Port

Remove the needle from the Liquid Culture injection port and insert it into the injection port on the grain spawn jar. Press on the syringe to expel the liquid mycelium into the grain spawn and remove the syringe. Wipe down the injection port and jar lid cover with alcohol and cover the jar lid with aluminium foil. Shake the jar well to get all the liquid distributed evenly in the jar amongst the grains. You want to avoid pooling of liquid inside the jar. Complete this process for all grain spawn jars, while using new (or re-sterilized) needles for each batch. Place jars in a clean, dark space with not too much airflow or traffic, at temperatures around 22-27 °C or 70-80 °F for incubation.

Step 5 : Allow Jars to Colonize. If Needed, Break and Mix Grain Spawn at 30% Colonization

After 3-4 days you should see some white mycelium peeking out from the grain, slowly colonizing the jar. If you injected a bunch of liquid culture into the grain spawn jar and mixed it well, then the mycelium growth should be pretty even across the grain throughout the jar, speeding up the time to full colonization. However, if the mycelium isn’t growing relatively evenly across the jar and there are large patches of grain which are not covered in mycelium, then there’s something you can do to help speed things up. When the jar gets to about 30% colonization, re-mix the grain inside the jar by tapping the jar against a book or a towel and breaking / mixing the grain spawn around. Do this only if necessary though, as mycelium prefer not to be broken up and banged around. The jars are considered “fully colonized” once all the grain is covered in mycelium throughout the jar. The jars pictured to the right are about 6 days into incubation at 26°C or 79°F. They are not yet fully colonized and don’t need to be broken up and shaken.
Colonizing magic mushrooms jars
Colonizing Magic Mushrooms Jars

Next Unit: Preparing, pasteurizing and inoculating bulk substrate for your fungi friends. Here you learn to make CVG substrate, mix it up with your colonized grain spawn and set up your monotub for incubation.

9 Responses

  1. Thank you for taking the time to author a very well-composed guide for each process of the growth cycle! I find this information to be very relevant and includes a trove of valuable pointers!

    I do want to note that with most of this craft there are variables that will work for some but not for others. It’s all about just getting started and finding what works. I live in such a dry climate that I can no longer work with monotubs, sadly. The moisture just gets sucked right out, regardless of systematic misting.

    On the other hand, there are many steps to the tek that must be followed to the letter as we are mimicking nature in an unnatural setting. I’m always researching to improve my process, and as I was reading through your directions I didn’t come across the size mason jars that you use? I may have missed it somewhere, but if that is not included would you mind adding that for clarification? I have used everything from half a pint to 2 quarts, and that makes a big difference in the amount of grain spawn available.

    I did want to ask about your method of shaking the jars after inoculation; I have heard this is a big no-no when using multi-spore syringes… but when inoculating with agar or G2G then it is most definitely encouraged. I personally don’t inoculate grain with multi-spore anymore as it proved to be a gamble regarding contaminant factors. That risk of course varies depending on where they are sourced and the sanitary practices used during collection.

    Regardless of how careful one is during this process, sh*t happens! Lol. 2 out of 5 times this worked without any contamination; however, since I was unsure of the culture prior to use I cannot rule out cultivator contamination (me, lol) or if errors in my prep were the cause of the problem.

    When the contam happens at the inoculation point of each jars it does make one wonder.. another reason why shaking after may be unfavorable as it would be difficult to see where these errors originate. Anyway, love your information, and this is most definitely appreciated! Not many sources out there with a plethora of knowledge in a one stop read. Keep sharing your light, the world is a better place because if it. Om

    1. Hi Violet. Thanks for the kind words! Yes, environmental changes can wildly affect the growing conditions, and throw off a set of precise instructions. To answer your questions, these are my thoughts and opinions:

      1) I use 1 quart mason jars, which are suitable for “canning”. Larger jars means more time for the inside of the jar to sterilize.
      2) I totally agree with you on the “direct from spore” growing method. It’s doable, it worked for me once or twice, but hides a lot of risk of contamination, especially as the process of spore printing is rarely really sterile. This is why agar is needed, to spread the spores and then choose a part which is known not to be contaminated. So if your jar is contaminated, shaking it wont change that, might just spread the contamination in the jar quicker…. but either way, your grow will be contaminated if that jar is used.

      Hope this makes sense, and good luck!

  2. Instead of simmering for hours, couldn’t you pressure cook the corn for a much shorter time? I read somewhere, 30 minutes at 15PSI

    1. Yes! You can actually pressure cook the corn (i do it for 15 minutes) instead, however there’s a good chance they will get overcooked and mushy unless you really have your timing right. You want to avoid overcooked and mushy.

  3. It annoys me to see this recommendation for shaking at 30%. After thousands and thousands of pounds of jars and (mostly) all-in-one bags, I have held close to the way I do it. I shake on day 5 after inoculation. I’ll do this with a 10lb bag, 5lb, 3lb or smaller, and even with jars on the rare occasion I’d work with them, as well as grain bags. I don’t know where this waiting for 30% originated, but it’s not necessary at all. I shake on day 5 and again on the 5th day after that, and then depending on how things look I’ll shake again in five more days. My timeline from LC inoculation using a 5lb all-in-one bag is almost exactly 30 days from inoculation to birthing the bag and putting it into fruiting conditions. Using white millet will also speed things along due to the larger surface area it’s able to cover as compared to the HUGE popcorn kernels.

    1. Every experienced cultivator has their own way to fine tune and optimise their process. Our website is geared towards helping newcomers grow their first flushes and as such, our process follows the “lowest common denominator” approach. For example, while smaller grain spawn (such as millet or birdfood) is much more effective at colonisation of substrate, it is also not easily available in stores and online retailers outside the USA. Popcorn however, is readily available all around the world. As for your 30% query – from my experience, the loosely defined 30% colonization “rule” is more suitable for larger grains such as corn, where you have less surface area for the mycelium to spread across more grain…which then requires more colonisation to happen before mixing it up. Personally, I usually add voluptuous amounts of liquid culture to my grain bags and mix them thoroughly only once – which is enough to get the mycelium spread all around the bag, without the need to break it up again before full colonisation. Saying that, it’s always good to hear from experienced growers about other successful ways of cultivation.

  4. Just want to say thank you for this valuable information. You are doing a huge service to beginner growers like myself 🙂

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