What is Mushroom Spawn?

Mushroom spawn is a substance that has been treated with mycelium to grow mushroom. Mycelium is a collection of cells that resemble a thread. Here’s a better description. Mycelium is what an apple tree is to an apple. It is the base for growing mushrooms.

You can use this spawn to move mycelium to any substance (substrate) if you want to grow mushrooms. You can utilize different substrates like logs, cardboard, straw, wood chips, and others.

The next question you want to ask yourself is if you can grow mushrooms from spawn without transferring to substrates. Well, you can, but it’s not the best approach. Some specific quantity of spawn can inoculate a higher amount of substrate. This can generate you more mushrooms compared to if you utilized spawn alone.

I provide everything you need to know about spawn in this article. But, I will quickly explain the different types of spawn and then recommend which type is considered suitable. Then, I will wrap it up with how to acquire and keep it.

Here we go!

Types of Mushroom Spawn

Spawn is any material treated with mycelium to vegetate mushrooms.

 Sawdust Spawn

People use sterilized sawdust and then treat it with mycelium using grain spawn. The sawdust is composed of different types of hardwood with different sizes and textures.

You can use sawdust spawn to inoculate mushroom beds, logs, cardboard, pasteurized straw, and different types of substrates. You can also use it to treat wooden dowels if you intend creating a plug spawn.

One notable advantage of this type of spawn is the particle sizes. Because of their size and quantity, you can derive many inoculation points that can ensure mycelium penetrates the substrate. This increases mycelium colonization and allocates little or no time for contaminants to infiltrate.

A side effect is that, solely, it is not nutritious and may not produce your expected yield. Therefore, you may experience setbacks if you attempt growing your mushrooms from only sawdust. So how do you increase yield if you decide to use sawdust spawn? It’s simple! You can enrich the sawdust with bran or utilize another nitrogen source to improve your yields.

Grain Spawn

Grain spawn can be defined as sterilized grain treated with spores or sterilized mycelium solution. Several forms of grain can be employed with millet and rye being the common types that are used. Other options include wheat, corn, and other cereal grains. Guess what! You can even try popcorn.

You can also utilize grain spawn to create more grain spawn, sawdust spawn, or treat different types of pasteurized substrates like straw.

The bottom line for using grain is that it has more nutrients compared to sawdust. This makes it suitable for growing mushrooms indoors or creating more spawn. Meanwhile, I would not recommend it for treating outdoor beds. Birds and rodents can easily target delicious grains, thus leading to a waste of effort.

Plug/ Dowel

These are small wooden dowels that have been treated with mycelium. You can use sawdust or the stems of live mushrooms.

A major benefit of plug spawn is its effectiveness in inoculating substrates derived from fibers or woods. It can readily colonize wood chips, cardboard, paper, logs, or stumps. Meanwhile, it is not an ideal choice for grain or straw-based substrates.

Other Forms of Mushroom Spawn

Straw spawn: This straw is pasteurized and treated with mycelium.

Sawdust spawn plugs: It takes the shape of a plug having Styrofoam at the tail end.

Woodchip spawn: It is derived from woodchip of different hardwoods.

Liquid Spawn: Water treated with mycelia slurry/mushroom spores.

So which of the spawn mentioned above is the best?

The Most Effective Mushroom Spawn

To answer your question of which spawn to go for, my answer will be to consider what kind of mushroom you are growing. The purpose should determine which type you should opt for.

Notwithstanding, ensure you match your spawn to the substrate. For instance, if you intend to grow mushrooms on logs, I would recommend you use sawdust or plugs. The rationale is that the mycelium can acclimatize with this substance, thus impacting the colonization time.

Some mushrooms perform better on some specific substrates. You will need to research the forms of mushrooms you intend growing to know the suitable substrate.

 Here are the most effective substrates suitable specific spawn

The listed examples should not be considered as a rule, but a recommendation. Therefore, be flexible when making your choices.

Sawdust: Wood chip beds, logs, cardboard, enriched sawdust, and non-pasteurized (outdoor) beds.

Grain: Enriched sawdust and pasteurized straw used in an indoor bed.

Plug/Dowel: Wood chips and logs.

A little bit of research before you can commence can save you a lot of stress in the end. You can start with something easier to enable you to appreciate the life cycle.

How do you acquire and store Mushroom Spawn?

You can buy mushroom spawn from different producers either offline or over the internet. Research for reputable producers so you can get the best quality. Spawn varies when it comes to quality.

You should have the inoculation date inscribed on your purchase.  Take note of this date as it may degrade due to bacteria, mold, or waste products. It is a ‘use or lose’ product, so its lifespan is limited to an average of 2 months.

Endeavor to use it as soon as you purchase it. Otherwise, you can refrigerate to extend its lifespan. But don’t forget that time is not on your side, so open that spawn and use it as soon as possible.

Meanwhile, purchasing is just for the occasional mushroom farmer, for those who want to own a big mushroom farm or produce at a commercial quantity, it may not be ideal to purchase. The best option is to make your mushroom spawn. It’s not complicated; you only require more sterile methods.


Mushroom spawning should be a sterile operation when growing mushrooms. Ensure you thoroughly clean your spawning tools, equipment, baskets, and other tools with a stream of water and disinfectants.  Ensure your garments; shoes are free of contaminants.

6 thoughts on “What is Mushroom Spawn?”

  1. I have enjoyed your tuition. I am going to put it in to practice. Thank you.
    Please can I be you friend?😄

  2. I found a patch of wild mushrooms (psilocybin ovoids) I bagged a couple gallons of “spawn” (mycelium covered wood chips) and I transported them to my home garden. I added fresh black wood chips, fire logs and manure and I’m steadily keeping keeping the area hydrated and shaded. What do you think my chances are of success?

    • Hello Sam, thanks for your message.
      First of all, I would make sure you are very certain of the mushroom species you have. Are they native to your area?
      Chances of success will depend on a lot of factors. I would say you should try to mimic the natural environment of the location you found them. That definitely will work for them. You can later tweak some variables to improve yield. Also, do not forget about the humidity.


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