Instructions for the Reishi Mushroom Kit Print E-mail
Sunday, 29 November 2009 14:26

Reishi in classic shelf form

Your Reishi kit contains live mycelium of the species Ganoderma lucidum, called Reishi in Japanese, Ling zhi in Chinese. These mushrooms grow on various dead or dying hardwood trees. You will prepare an artificial growing environment that simulates the conditions in a dead or dying tree trunk or branch by combining hardwood sawdust, water, and coffee grounds.


Contents of the kit:

  • poly bag of live Reishi grain spawn
  • bag of hardwood sawdust pellets (including supplemental limestone and gypsum)
  • poly filter bag

Additional materials you will need:

  • about two cups of freshly-used coffee grounds, drained of excess moisture
  • a clean mixing bucket or bowl of a least 1.5 gallon capacity
  • a thermal food storage sealer, strong adhesive (e.g., duct) tape, or clamp (clothespin or chip clip)
  • isopropyl alcohol solution (optional)
  • three cups of hot tap water*

Preparing the Substrate

  1. Collect your coffee grounds. Drain them of any free-running liquid, so they remain moist but not sodden. If you need to collect them over time to get enough, keep them in the refrigerator or freezer in a closed container until you have the 2 cups you need - but thaw them to room temperature before using them!
  2. Choose a workspace where you can minimize the amount of air movement. Turn off fans, close windows, and keep others from entering while you work. Prepare your materials and your workspace so you can work quickly to minimize the exposure of the ingredients to airborne contaminants. You don't need a sterile environment, just a reasonably clean and quiet one.
  3. Before mixing the substrate, wash your hands thoroughly with soap and water and wipe them with alcohol solution to reduce the chance of contaminating the mix. It's a good, but not strictly essential, practice to give all the surfaces that will come into contact with the mix, like the mixing container and table top, a wipe-down with an alcohol-moistened paper towel.
  4. Empty the bag of sawdust pellets into your mixing container. Take the hot water from your sink and add it to the sawdust pellets and mix them up by hand or with a clean mixing spoon until they break apart.
  5. Add the coffee grounds to the bucket and mix well. If the mixture still feels warm, let it cool to room temperature before continuing.


  1. Squeeze the bag of grain spawn to break apart the grains. Cut open the bag, pour in the spawn, and mix it in quickly but thoroughly. Break up any remaining clumps in the mix.
  2. Pour the mixture into the filter bag then seal it tightly. Use a food storage thermal sealer if you have one, otherwise fold the top inch of the bag over and tape or clip it securely. Don't tape over the filter patch! There should be plenty of space in the top of the bag for air to circulate. If the airspace collapses, pull the sides of the bag apart to draw air in through the patch until the sides of the bag near the patch do not cling together.



Place your bag of mycelium in a safe place where it can incubate at room temperature. 70°F is ideal, but your Reishi can thrive during this phase at any temperature between 60°F and 80°F. It requires no light or watering during this period. Within days you will see the mycelium grow from the individual pieces of grain and eventually throughout the bag, forming a thick, essentially solid white mass within a week or so.


After about 30 days your Reishi mycelium will be ready to start fruiting. 


Your Reishi may begin forming primordia - the earliest visible form of the mushroom fruiting body - on its own, without any intervention from you. Initially these take the form of pure white lumps the size of a finger or thumb tip.

To get them to form properly, you need to give your Reishi light. About 30 days after starting your kit, put it where it will get indirect sunlight or artificial light.  If it has not started forming fruiting bodies yet, you can influence how it does so by how you choose to allow outside air into the bag.

In the carbon-dioxide rich environment inside the bag, the Reishi primordia will eventually form on the top surface of the substrate and grow toward the filter patch, which provides the nearest source of oxygen-rich outside air. You can let them start this way, then redirect their growth by cutting new openings in the bag closer to the stalks, which will cause them to turn and grow toward the new openings, eventually growing into the outside air and forming the classic shelf-like body. Using this approach you can get your Reishi to produce some fascinating shapes.


To produce the classic shelf form more directly, you can fold the top of the bag down, closing off air flow through the filter patch before the primordia have formed, and cut openings in the side(s) of the bag below the top of the substrate, and the mycelium will form fruiting bodies at the site(s) of the holes and grow directly out. Once you have cut openings in the bag, begin misting the exposed surfaces with water several times a day. 


Reishi fruiting bodies form slowly, taking three weeks or more to mature, longer if growing at cooler temperatures. It can endure lower humidity than the oyster-type mushrooms, so it usually does not suffer much harm if you neglect to mist it occasionally. It grows tenaciously. 


The active growing surface of the fruiting body remains white, while the rest of it darkens. When the wite leading edge starts darkening, your Reishi is ready for harvest. 


Cut off the Reishi fruiting body where it emerges from the mycelial mass. Either use it fresh to make teas or soup, or air-dry it. Some people cut them into small pieces while still fresh and workable, then dry it, so the pieces are ready to drop into hot water for tea. Others dry the whole thing, then scrape of bits for tea, or grind it up. Once dried it becomes quite tough and leathery and difficult to cut. Once it's thoroughly dried, store it in a sealed container.

After you have harvested your first batch, keep misting the bag of mycelium and in a week or two you may see more primordia beginning to form. Cultivate them as before. You typically won't get more than two flushes.



Eventually your substrate will get contaminated by other organisms - mold, bacteria, even algae. You just cannot keep them all out. Unless contamination gets way out of hand, your mushroom will probably still flourish.

Contamination will appear as areas of green, blue-green, yellow, orange, red, brown, or black that increase in size and overrun the white mycelium. Ideally, your kit will turn from sawdust-and-coffee brown to white, with a pale yellow fluid appearing when it's mature. Anything else probably results from contamination. As long as it doesn't seem to overwhelm the mycelium, everything will probably turn out fine.

It helps to think of growing mushrooms as a contest between the many organisms that can grow in the substrate you have provided. Your kit contains a relatively large amount of grain spawn for the volume of substrate you prepare, which greatly increases the odds that your fungus will overwhelm any competitors that might gain a foothold. But there's no guarantee. Too much water, too little air, ingredients left out on the counter collecting contaminant spores - lots of things can diminish the advantages your mushroom culture enjoys. For that reason we recommend that you follow these instructions as closely as possible. Don't start to improvise until you have gone through the process successfully once or twice!


*if you have heavily chlorinated tap water, let it sit for a day to lose its chlorine, or use bottled spring or well, but not distilled, water


Last Updated on Friday, 25 May 2012 15:03