EducationFungiProcessing & Food Preservation

Petri Dish Mushroom Cultures


Everyone is at least somewhat familiar with the plant kingdom but the fungi kingdom is very little known and understood and yet the more we look into mushrooms the more they seem to offer. Some mushroom species have the ability to clean up serious toxins in our environment and some offer valuable medicine. They all play a part in the decomposition process by pulling apart lignin and cellulose in fallen trees and woodchips in our garden.

Growing mushrooms is both an art and a science. At times they can be tricky and uncooperative and other times when you’re just about ready to give up on them they’ll surprise you with the biggest, tastiest crop you’ve ever seen.

For a while I was making mushroom kits so that people could grow gourmet mushrooms at home. It was a fun job and really pushed my education in mushroom cultivation forward but it never felt all that rewarding. I much prefer teaching people the process so that they have the skills to grow gourmet mushrooms from scratch. Teach a person to fish right?

It all starts with mycelium. The more mycelium you grow the more mushrooms you grow so the process of mushroom growing can be seen as different steps to expand your mushroom mycelium. Mushroom cultivator their own method. I like to keep it simple and straightforward. You can start the mycelium growing process in a number of different ways but the most tried and true method is growing them on petri dishes.

Growing Mushroom Cultures on Petri Dishes

First I mix the media that I use to pour into my petri dishes. You can use a handful of different ingredients but I prefer to use malt extract powder, agar agar and a pinch of yeast.


Then I need to heat the agar media mix up on the stove and pour it into a glass bottle.



Next I need to sterilise the agar media and my reusable petri dishes in my trusty pressure cooker. This process wipes the slate clean and gives my mushroom mycelium a head start. If I didn’t sterilise my agar media and dishes then all I would grow would be mold and bacteria.


Then I need to move the now sterilised agar media to a clean space. Professional mushroom growers have clean rooms and expensive fans and filers. I have a plastic tub!


I wait for the agar media to cool to a comfortable temperature to handle, and then pour the still hot liquid into the petri dishes. If you wait until the agar media cools too much it will set inside the glass jar and you won’t be able to pour it.


As the agar media cools inside the petri dishes it sets, creating the perfect environment for mycelium to grow! After it has cooled and set the next step is to clone a fresh gourmet mushroom. I always recommend starting with oyster mushrooms. In my experience they are the easiest to grow and it’s always good to start with a win!


The small piece of mushroom will revert back into mycelium and will start to grow over the agar media inside the petri dish. At this point I keep a very close eye on the petri dish mushroom cultures. If there is any sign of mold or bacteria I need to go ahead and clean up the mushroom culture before moving onto the next step in the process, growing grain spawn and then finally onto growing gourmet mushrooms!


There are a number of different ways to learn the process of gourmet mushroom cultivation. I learned most of what I know from years of study and experimentation and dozens and dozens of projects.

We have just finished putting together an online video course walking through the ins and outs of Petri Dishes for Mushroom Cultivation and are in the process of finishing up the next step Growing Grain Spawn.

Happy Growing!

Todd Mansfield has been growing, and teaching people how to grow, gourmet and medicinal mushrooms for over 5 years now, commercially and as a hobby. He has had experience growing organic swiss brown mushrooms on a small commercial scale, managing a shiitake log-growing enterprise and running an online boutique spawn and mushroom culture supply business. He is dedicated to making mushroom cultivation sustainable and easy.

Todd, is currently offering an online course for learning to grow gourmet and medicinal mushrooms at home starts with learning how to grow Mushroom Cultures. This online course, 3 hours long is based on 11 videos delivered in HD video and will teach you the essential skills to grow your own Petri Dish Mushroom Cultures at home.

If you’re interested in the course check it out here- .


  1. Love your article… I want to start growing my own mushrooms, I hope I can begin soon and take that 3 hourscourse…

    Thanks for sharing

  2. Why are there no pictures of mushrooms actually growing out of petri dishes in the article? It sounds kinda strange to me.

    1. Growing mushrooms comes well after the petri dish culturing stage. All the article and the course covers is that first stage of growing mushroom mycelium on petri dishes. After you’ve mastered that stage it is quite easy to go on and grow mushrooms on an actual growing medium (straw, compost, logs, woodchips, sawdust etc)

  3. Todd,
    Have you written any books on mushroom cultivation? I read tons of info on the hobby, but I read online groups and forums the most. I’m very much into strain isolation and have 6 varieties of monoculture in my fridge. I’m looking for a book on more advanced mycology or even an online course. Specifically pertaining to testing and creating contaminant resistant monocultures or maybe even mushroom genetics. You are an inspiration because I love this hobby and would love to work in this field. Thank you in advance for your resppnse.

  4. Great simple step article, thank you! May I ask if those are a regular type of deli container you are using as your petri dish?

  5. Very interesting article and straight forward. Thanks for sharing such nice information. I would like to find out something, at what temperature do you store the petri dishes after they are fully grown?

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