How to Make Your Own Mycelium Jars

Mycelium is the branching structure of a fungus that draws nutrients and moisture to feed the part of the fungus that will bear spores, such as the portion of the mushroom most people are familiar with. If you think of it in terms of flowering plants, the mycelium is like the root that obtains food for the flower. To grow mushrooms at home, you can either purchase a commercial mushroom kit or you can start from scratch with a mycelium jar.

Dip the cotton swab into the starter culture. Swipe the cotton swab across the agar.

Cover the petri dish and turn it upside down. Store it at 25.6 to 30 degrees Celsius for one week. After a week, there should be a layer of white, stringy material. This is the mycelium inoculant.

Pour the rye grain and water into the jar. Allow to sit at room temperature overnight.

Use the teaspoon to scoop out a small chunk of the agar that has mycelium growing on it. The piece doesn't need to be more than half an inch square. Drop the piece into the jar.

Put the lid onto the jar and shake the jar to mix the contents. Loosen the lid enough to allow air into the jar.

Place the jar in a dark area where the temperature will remain at 78 to 85 degrees Fahrenheit. Every three days, tighten the lid and shake the jar. Loosen the lid again after each shaking. After about two weeks, the jar will be colonised with mycelium.


Everything must be kept as sterile as possible to prevent cross-contamination. Wash your hands before every step and clean your work surface thoroughly before and after working with the mycelium. The starter culture can also be injected directly into the jar, but growing it on agar first lets you verify that the starter will work.


After two weeks, your jar should smell like mushrooms. If there is any odd or foul odour, your jar has been contaminated and you should re-sterilise everything and start over.

Things You'll Need

  • Petri dish of sterile agar
  • Psilocybe cubensis starter culture
  • Cotton swab, sterilised
  • 500ml wide-mouth jar with screw top lid, sterilised
  • 130 grams sterilised rye grain
  • 100ml water
  • Teaspoon, sterilised
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About the Author

Based in Portland, Ore., Tammie Painter has been writing garden, fitness, science and travel articles since 2008. Her articles have appeared in magazines such as "Herb Companion" and "Northwest Travel" and she is the author of six books. Painter earned her Bachelor of Science in biology from Portland State University.