How to use Liquid Culture

Feeling a little nervous about making grain spawn for the first time? Not to worry - we're here to help you through it! This blog will provide step-by-step mushroom cultivation tips to help you successfully create a mushroom spawn bag. Let's get started!

There are many ways to inoculate your grains. Inoculation is simply the act of adding your culture onto a substrate, like grains. You could use an agar culture, liquid culture, liquid inoculant, spore syringe or spawn.


You could classify the grain inoculation methods into two types:

1. Liquid Cultures, Spore Syringes, and Liquid Inoculant

You do not need a sterile environment to use this method. It is quick and easy and very effective. However, if you receive a culture from a non-reputable source, there is a chance that the culture isn't as clean as it should be. Spore syringes are especially renowned for their high contaminant risk. If you are unsure whether your culture is clean, you will need to test your culture on agar to ensure that the inoculant is not contaminated before using it to inoculate your grain bag.

Myterra Labs liquid cultures (Click here for the link) are quality controlled through every process to ensure clean cultures. All of our cultures are fully traceable, meaning that we now exactly where the cultures came from, how old they are, and what they are capable of producing. We highly recommend using these cultures to grow mushrooms - it's easy!


2. Agar or Spawn

The Myterra Difference

This method of inoculation has the lowest risk of contamination when performed in front of a laminar flow hood, but can be performed in a still air box, or Noc Box. The inoculants that are put into the bag after cutting off the top of the grain bag are: Agar culture and colonized spawn. Colonized spawn cultures can be expanded by adding them to grain, but you should only do this once or twice to avoid putting your culture into dormancy. 




Here are a list of tools you are going to need to successfully inoculate your grain bag with a syringe:

  • Myterra Labs Liquid Culture
  • Adhesive injection port (included with Myterra Labs Grains)
  • Gloves are good practice, but not strictly necessary



All Myterra Labs substrates are sealed and packaged in a HEPA-filtered clean room. Myterra Labs grain bags are sealed inside of a protective white bag to prevent dehydration of the substrate and denaturing of the chemical composition of the substrate. You will need to remove the white outer packaging before inoculation. 

BE CAREFUL when removing the outer packaging to avoid puncturing the unicorn bag inside. Hold one of the corner flaps of the white bag and use your scalpel/knife/scissors to make a cut underneath the seal of the bag. You will be able to peek inside of the white bag to see the inner unicorn bag and can continue cutting the bag whilst making sure not to puncture the inner bag.



Wipe the outside of the unicorn bag with the alcohol swab included with your liquid culture, focusing on the area between the filter patch and the surface of the grain.

Remove the backing on the injection port and stick the port onto the bag about an inch below the filter patch, above the surface of the grain. Once attached, wipe the injection port with the alcohol swab.



Clean your hands before starting this process. Remove the needle from its sterile packaging (keep the needle capped) and twist it onto the tip of the syringe. Be quick during this process and DO NOT touch any part of the needle or tip of the syringe during this process. Anything that touches the tip of the needle should be sterile, otherwise you risk contaminating your culture.



The best method that works for us with a liquid type of inoculant is to spray the surface of the grains with the liquid culture. Use your needle to pierce the injection port, face the needle towards the surface of the grains and slowly depress the syringe plunger. While depressing, move the tip of the needle so that you are able to spray all over the top surface of the grains. You can use as little as 5ml of inoculant, but be aware that the colonization process will be slower with smaller amounts of inoculant. We find that 10-20ml of inoculant has the fastest colonization time. Remove the needle once you have added your inoculant and dispose of the needle safely. DO NOT shake the bag.

As a precautionary measure, tape over the injection port with a piece of packing tape. This will prevent the injection port from possibly falling off when the bag is shaken at a later stage.



Leave the bag unshaken until you see white mycelium form on the top of the grain. Some species, like Lion's mane will have very thin wispy mycelium which can be hard to see. You can shake the bag once you see that the mycelium is growing well (~1 week). Shaking the bag ensures that the mycelium is spread throughout the bag. You will need to shake the bag again once the bag is about 50-60% colonized.