Sterilized Grain


Shipping time maybe up to 1 week. Do not order unless you are able to wait. This operation isn't Amazon Prime. Its a small business during a pandemic. We do not keep inventory to ensure product freshness. We make the grain to order.


SEE UPDATE July 8th 2020

Product Description

This sterilized hydrated grain is the perfect item for growing a bulk amount of mushrooms. We have taken all of the struggle, cost and work out of preparing the perfect grain substrate yourself and left the fun part for you.

Quickly getting perfectly made grain for spawn production for the new grower or the experienced but busy mycologist has never been easier or cheaper.

This milo grain is hydrated, sterilized, and is ready for inoculation. It comes in a sealed spawn bag with an injection port to make inoculation by liquid culture or spore suspension as quick and easy as it ever will be!

Important note about replacements

Occasionally the rigid corners of the bags get damaged during transportation. This can lead to contamination.
So if the bag contaminates before inoculation, we will replace it free of charge. Just send us a picture of the bag. Include the injection port in the image.

If the bag contaminates after you inoculate it, and you believe that it wasn't your fault, send us a picture and we will replace it for our cost. This will be $1.75 for the replacement bag, plus the shipping. To save on shipping we recommend buying more or having it replaced when you buy more as shipping one single bag costs $6.30, while shipping 8 bags only costs $2.07 per bag.


Simply inject some of spore syringe or liquid culture of your choosing through the provided injection port and wait for it to grow! We often see full colonization in one week.

Why Milo?

Milo is ideal for making mushroom spawn— We believe it is even better than rye for several reasons. Milo yields more inoculating points than other grain due to Milo's harder shell, and higher amylose starch, it is less sticky and breaks apart more easily allowing you to mix it thoroughly into your bulk substrate. Rye and other related grain has a starch in it that is stickier, which in addition to the rye seeds softer coating results in more difficulty breaking it up properly for ideal spawning.
Our Milo grain promotes rapid colonization, leaving contaminants with less opportunity to gain a foothold in your substrate.

We use it ourselves!

We use this product to make many of our oyster grow kits. We mix the colonized milo into shredded, hydrated and pasteurized straw, using just one pound of spawn for every fifty pounds of prepared straw. That means that your three pound bag can inoculate, at a two percent spawn ratio, one hundred and fifty pounds of prepared substrate, which can yield fifty pounds of oyster mushrooms! Many other mushrooms have a similar spawn ratio, though not all.

Technical specifications

The technical info below are approximations good enough for most mushroom grow operations.

Filter patch: 0.2 micron
Bag size: 5x4x19
Seal: Bag is sealed twice with a double sided heat sealer that is 10mm wide, yielding a total of 20mm (~0.8 inches) wide seal strip.
Moisture content: ~55%
Approximate protein content: ~5%
Grain: Red Milo Seeds (Sorghum bicolor, 615 grams)
Water: Municipal, 748mls
Additives: Gypsum, small quantities of pulverized coco coir, peat moss, sawdust, and straw.
LC/Spore Tolerance: Each bag can receive as much as 12ml of liquid culture or spore suspension without any issues. This assumes you allow the bag to expand and that it is shaken after inoculation. We recommend 0.5 to 3ml of liquid inoculate, but if time is an issue, more can speed up colonization rates.
Sterilization Method: 15 PSI for a minimum of 90 minutes.
Number of seeds (inoculation points) per bag: Average is approximately 17,000 seeds, but range is 15,990 to 18,750 seeds depending on grain size and weight added to bag

Volume including air gaps: ~1800ml - This volume is approximately 2.5 quart jars that are filled 75% full of grain.
Actual volume: 1300ml
The actual volume is useful for figuring out the volume when adding to substrate that is made of small particles such as coco coir, coffee grounds, or sawdust as the particles fill the gaps between the grain. In this case, adding 1800ml of the shaken grain to a fine particle substrate is likely to only increase the volume by 1250ml to 1350ml. If your bulk substrate is large and has gaps greater than the grain, such as is often the case with straw, the addition of grain may not cause a volume increase.

Inoculation & Colonization Service

You can also purchase fully colonized spawn bags with the species available, but this will result in at least a 2 week delay as we make it after it is ordered to ensure the quality of the product. If you are purchasing additional items from us in the same order, they will also be delayed by 2 weeks. You may find it is better to purchase the grain spawn in a separate order.

The grain in our grain spawn is as described above. It is then inoculated with liquid culture using a sterile needle in a clean room, under a biological grade laminar flowhood. Before sending it off, we examine it to ensure there is no bacteria or other fungi present.

We work hard on making it as easy as possible for you to grow mushrooms, so we also offer a service to inoculate and colonize the grain for you. After approximately two weeks, you'll receive fully colonized, ready to use spawn.

Custom Designed Grain

We realize that not all grain is perfect for all situations; you might want it to have a higher or lower moisture content depending on what you are doing - Just let us know, and we'll be happy to adjust the moisture content for your order. This service is free, but it may cause a delay.
In our experience

Ordering 2 Bags vs 3 Bags
The problem with ordering 2 bags is that mailmen will often forcefully shove the smaller 2 bags into the mailbox and we've had reports of this damaging our bags. They come in a padded envelope. If we use a larger box to alleviate this problem, it makes the shipping cost the same as shipping 3 bags, but then requires additional padding & labor of packaging the item. We prefer to send 3 bags instead, as this is a better deal for the customer, creates less waste, and is easier for us.