Grain & spawn 3 min read
Sterilised grain bags explained: what they are, how to use them and how to keep them clean
The injection port, the filter patch, the 2 to 5 ml, the three weeks. Everything a grain bag does and everything you do to it.
AMK Store Est. 2026
Sub & grain fit for a kingdom.
Sterilised grain and premium CVA substrate for gourmet and medicinal mushroom growers. All-in-one grow bags, pre-poured agar, cultures and grow kits are on the way.
- Sterilised
- Injection-port grain bags
- Filter-patch sub bags
The staples
EVERY GROW STARTS WITH THESES STEPS
STEP 01• CHOOSE WHAT CULTURE YOU WANT TO GROW
The range
Everything for the grow.
Build your grow
How much grain do you actually need?
Tell us how much substrate you are filling and the spawn ratio you like. We will work out the grain, pick the cheapest mix of bag sizes, and bag the lot in one click.
Substrate
Grow docketAMK Store
2.5kg grain
+
5kg substrate
Total$0
Bag mix is the cheapest combination of our bag sizes that covers what you need.
Grain guide
Pick your grain.
Four grains, one standard. Here is how they compare, in grower terms.
How it fits together
Plate to harvest in four moves.
-
01
Inoculate
Introduce your culture to a bag of sterilised grain through the injection port.
Sterilised grain -
02
Colonise
Let the mycelium run through every kernel until the bag turns white.
Agar for clean starts -
03
Spawn to sub
Break up the colonised grain and mix it through your substrate.
Premium CVA substrate -
04
Fruit
Give it fresh air, humidity and light, then harvest your flush.
All-in-ones do 01 to 03 in one bag
The culture library Coming soon
Gourmet & medicinal, on the bench.
The library is being catalogued now. Join the drop list and you will hear the moment it opens.
The kingdom standard
Made properly, bagged properly.
Sterilised
Grain and substrate both arrive sterilised and sealed, ready to use.
A refined recipe
Our CVA recipe has been refined over years of growing for consistent results.
Nutrient-enhanced grain
Prepared with proven methods and carefully selected nutrients for a strong start.
Proper bags
Grain bags carry an injection port. Substrate bags breathe through a filter patch.
Questions
Good to know.
Something not covered here? Ask us and we will add it.
What is the difference between grain and substrate?
Grain is what you inoculate first. Once the mycelium has colonised it, that grain becomes spawn, and you mix it through the substrate: the bulk material your mushrooms fruit from.
Which grain should I choose?
Wheat is the all-rounder. Oats and milo break apart easily, and milo gives you the most inoculation points per kilo. Corn has the biggest kernels. The grain guide compares all four.
How much grain do I need for my substrate?
It depends on your spawn ratio. At 1:2 you use one part grain to two parts substrate, so 5kg of substrate takes 2.5kg of grain. The grow builder does the maths and picks the bag sizes.
What is an all-in-one grow bag?
Sterilised grain and substrate layered in one bag with an injection port. You inoculate the grain, let it colonise, then mix it through the substrate without opening the bag. They are coming soon.
How should I store my bags?
Keep them sealed, somewhere cool, clean and out of direct sunlight, and use them soon after they arrive.
When do cultures, agar and grow kits land?
They are being prepared now. Join the drop list and you will hear first.
Shop all
Sterilised grain, premium substrate and everything coming next.
Step 02 • choose your grain
Sterilised Grain
$351kg bag · $35 per kg
Nutrient-enhanced grain, sterilised and sealed in injection-port bags. Wheat, oats, corn or milo.
1
- Sterilised and sealed, with an injection port
- Enhanced with carefully selected nutrients
About
We offer a premium selection of sterilized grain, carefully prepared to consistently support fast, healthy and vigorous mycelial growth. Our grain is produced to exceptionally high standards using proven preparation methods and is enhanced with carefully selected nutrients to provide optimal growing conditions.
With a strong track record of reliable performance, our sterilized grain is designed to give your mycelium the best possible start and deliver consistent results you can rely on.
Details
- Sizes
- 1kg or 2kg
- Grain
- Wheat, oats, corn or milo
- Prep
- Sterilised, nutrient-enhanced
- Bag
- Sealed, with injection port
Pairs withPREMIUM CVA SUBSTRATE
What this bag is for
This is the bag you inoculate. Inside is hydrated, nutrient-enhanced grain that has been through a full autoclave sterilisation cycle and sealed behind a 0.2 micron filter patch, with a self-healing injection port on the front. Inject a liquid culture through the port, keep the bag warm and dark, and the mycelium runs through every kernel until the bag is white. That colonised grain is grain spawn, the thing you mix through a substrate to grow a flush of mushrooms.
Sizes and prices: 1kg for $35 and 2kg for $55. Grain: Wheat, Oats, Corn and Milo. Prices in AUD, GST inclusive where it applies, shipped tracked Australia-wide.
How to use it
- Inoculate
Wipe the port with 70% alcohol. Flame the needle until it glows, let it cool for a few seconds, then push through the port and inject 2 to 5 ml of liquid culture. Spread it across two or three spots if you can.
- Colonise
Keep the bag at 20 to 26°C, out of direct light, with the filter patch unobstructed. Do not squeeze it in the first week. When a third of the grain is white, break the bag up gently so the mycelium spreads, then leave it to finish.
- Spawn
When the grain is fully white and smells clean and mushroomy, it is spawn. Break it up and mix it through substrate at 1:2 to 1:4 by weight. The grow builder picks the ratio and the bag sizes.
Which grain: wheat, oats, corn and milo?
Wheat is the all-rounder with small, even kernels and plenty of inoculation points. Oats keep their husk, stay loose and shake apart easily once colonised. Corn has big kernels with big reserves. Milo (sorghum) is tiny, tough and gives the most inoculation points per kilo, which means the fastest spread. If you have not got a preference, start with wheat. The grain guide compares them meter by meter.
Questions
About this product
How much liquid culture do I inject into a 1kg bag?
2 to 5 ml is plenty. More injection points help it colonise faster; more volume does not. Keep the needle flamed and the port wiped.
How long does it take to colonise?
Oysters: 10 to 14 days at a warm room temperature. Lion's mane and shiitake: three to five weeks. Colder rooms slow everything down.
Can I use spores instead of a liquid culture?
This bag is made for liquid culture or agar transfers of gourmet and medicinal species. Spores germinate slowly and unpredictably in grain; germinate them on agar first and send a clean isolate to the bag.
How should I store it before use?
Sealed, cool and out of the sun. Use it within a couple of weeks of delivery; the fridge is fine for short holds, just let it warm to room temperature before inoculating.
What is the difference between this and colonised grain spawn?
This bag is sterile and empty of mycelium: you add the culture. Colonised grain spawn has already been run through with a species and is ready to mix into substrate.
Guides for this product
All guidesGrain & spawn 3 min read
Which grain is best for mushroom spawn? Wheat vs oats vs corn vs milo
Four grains, one standard. The differences are real but smaller than the forums suggest, and they mostly come down to kernel size.
Checkout
A few details, then you pay on a secure page.
The drop list
Join the kingdom.
Restocks, new cultures and first dibs on grow kits. One email when something lands, nothing more.