Reishi is one of the best known and most studied medicinal mushrooms, often referred to as the "mushroom of immortality". Our understanding of its healing potential stems from thousands of years of use in China, Japan, Korea and other Asian countries. Luckily we can grow reishi at home, whether you've got some outside space or not. And, it's intrigue doesn't stop there. It's also a great fungi to use as a mycomaterial for building, design, and art!
Description: Reishi are polypore mushrooms and are woodier than many other forms of fungi that emerge from the ground overnight. That toughness helps them persist throughout the season but makes them too difficult to chew.
There are several species that we refer to as reishi, all from the Ganoderma genus, including but not limited to: Ganoderma lucidum, Ganoderma tsugae, and Ganoderma multipileum. We can learn a lot about these species by looking at their names. In latin, gan means shiny and derm means skin, pointing to the resinous or lacquered looking surface of these mushrooms. Similarly, lucidum evokes luminosity. For its part, tsugae relates to a preferred substrate, the hemlock tree. Those of you already familiar with mycological terminology may know that a pileus is a cap, so multipileum offers us a multitude!
All of these species have these features in common: a burgundy red cap which emerges in a knobby fashion, often fading into orange and then white at it's growing tip. The surface looks shiny or varnished, fading in age. Beneath the cap is a white, tightly-pored surface which bruises brown and releases medium brown spores. The flesh is white while the pore surface is medium brown.
Depending on gas exchange, reishi caps can take on different forms. High oxygen environments produce classic conch shapes, circular or kidney forms. Where carbon dioxide dominates, antlers emerge.
Image credit @Siobhantrails on Instagram
Ecology: Reishi are a white rot fungi that grow on trees, primarily hardwoods with the exception of G. tsugae which grows on hemlock. It may be parasitic on live wood, especially oaks and maples or saprobic on dead wood. We see them most often on stumps, fallen logs, or at the base of living trees. Unlike hardier polypores, reishi are annual, only releasing their spores once before beginning to decompose themselves.
In nature, distribution varies by species. G. lucidum is native to forests of China and Europe, though some introduced or escaped populations exist in Utah and California. Similarly, G. multipileum is native to tropical regions of Asia. The more widely occurring reishi in the US and across North America is G. tsugae among conifer stands.
If you're curious about recent insight into the Ganoderma of North America, check out the research of Andrew Loyd and contributors, who've made strides in clarifying their taxonomy. They've outlined 12 species in the US from recent collections!
Difficulty for Outdoor Cultivation: Advanced
Preferred Growing Methods: Reishi can grow using any of the log methods: traditional drill and fill style, totems, stumps, and by trenching or burying your logs. Though they seem to really benefit from at least partially burial. If sourcing wood is challenging, you can bury a Reishi Grow Kit or Sawdust Spawn block and get some awesome fruits, too!
We recommend waiting until logs are well colonized before burying your logs in soil. You can check if they're ready by looking at the cut ends to see if it's mostly covered in mycelium. Depending on the size of your log, it may take 6 months to a year of growing before the burying can begin.
The process for trenching is simple: Dig out an area half as deep as the diameter of your logs in a shady area and keep that soil. Arrange your logs in the trench so they look like a raft. Then use the soil to pack in between and around the logs until only the top surface is still exposed. Water the area so the material around your logs compacts and add more if necessary!
Substrate: Reishi prefers to grow on dense woody material. G. lucidum will grow on several hardwood species, but really thrives on sugar maple and sweetgum. G. tsugae on the other hand should be grown on hemlock but it's worth experimenting with growing on other Pine family trees. Find a full tree species compatibility chart here.
As always with log inoculation, use freshly cut wood for the best success! And avoid felling trees after spring bud break through full leaf out. For more information on timing wood harvest and inoculation, follow this link.
Temperature: In commercial operations, fully colonized and short inoculated logs or sawdust blocks are buried in a grid in a low tunnel or greenhouse. That environment creates a warm, humid climate perfect for fruiting. Northern or more temperate areas may benefit from a little help with heat in this way, since G. lucidum prefers to fruit in warmer temps, especially in late spring through summer.
Mycelium Formation: Reishi mycelium is white, linear, and strong as all get out. It can form leathery mats and often yellow or orange droplets may appear as exudate is released. In more maturity, the mycelium grows so dense it becomes rock solid. These qualities make it an excellent fungi to work with for building materials. In fact, one student in Ohio, Katy Ayers, crafted a functional canoe from reishi. It fruits after each dip!
Image credit @BewilderSG on Instagram. Kiat's reishi light!
Fruiting Information: When reishi beings to emerge, it resembles felt tipped knobs, probing its environment. These initial stems may form the signature conch shape if there's enough oxygen present and remain as antlers if not. Reishi are determined and strong mushrooms that will burst through bags in search of air. Still, they're slow growers, so use patience while you watch them take form. Manipulation of gas exchange and light can shape the fruiting body in interesting ways!
One grower in Singapore, Kiat of Bewilder, has combined innovative uses of G. multipileum as both a construction material and sculptural element to create elegant and intriguing light fixtures! His work provides inspiration for the many under-explored applications of fungi.
Harvesting: The margin of reishi, where it's growing from, will dull from white or orange to a more matte red in maturity. Around this time, it'll release a dump of spores. Since reishi are woody, they're more forgiving with harvest timing and our fleshier fungi. Pick them when they've reached the size or shape you like up until a little after they've reached peak maturity and start to dull. Though its worth noting that mushrooms picked with their white edge intact will probably store better. Snap or use a sharp knife to cut the reishi at the base of the stem.
Medicinal Qualities: In traditional Chinese medicine, reishi is used as a warming tonic and gentle detoxifier. As an adaptogen, it helps to manage stress and hormone levels, and soothe the nervous system. (1) At least 400 different bioactive compounds have been isolated from reishi, most notably a suite of peptidoglycans, triterpenes, and polysaccharides. (2)
Perhaps the most well known property of reishi is its ability to support the immune system. It does this in a two-fold manner. As an immune modulator, it both boosts the system when it's struggling and reins it in when it's overactive. For this reason, it's a popular supplement to cancer therapy. Additionally, studies have shown that reishi may help lower cholesterol, regulate blood sugar, support liver and lung function, and provide antioxidative protection from free radicals. (3)
Preparation: Since reishi are on the tough end of the mushroom texture spectrum and they're pretty bitter, we like to make a tea or decoction from them. Simmer a few fresh or dried pieces in 3 cups hot water for an hour, longer for a stronger brew. To cut the bite of the bitterness, stir in some honey or maple syrup. Combine with chaga or some of your favorite flavorful plants (we like licorice root and ginger) if you're feeling fancy!
In the doldrums of winter, a favorite remedy of ours is to make a rich medicinal mushroom broth. Mix several pieces of reishi in with other favorites including shiitakes, lion's mane, or a scoop of chaga. Add carrot, celery, onion, and garlic. If you save vegetable or meat scraps, throw them on in! Simmer on low for a few hours or leave in a slow cooker overnight. Strain well and use as a stock for soups or drink warmed for a little nourishing boost.
You can even take your medicine making a step up and make capsules or tincture from your harvest. For more creative ideas on how to incorporate reishi into your routine, Healing Mushrooms: A Practical and Culinary Guide to Using Mushrooms for Whole Body Health is a great reference!
Reishi mushroom growing in a greenhouse. This image was provided with permission from Nammex.
Grab some Ganoderma
(1) The Fungal Pharmacy: the Complete Guide to Medicinal Mushrooms and Lichens of North America, by Robert Rogers, North Atlantic Books, 2011, pp. 172–184.
(2) Zhou, Xuanwei. (2017). Cultivation of Ganoderma lucidum: Technology and Applications. 10.1002/9781119149446.ch18.
(3) Wachtel-Galor S, Yuen J, Buswell JA, et al. Ganoderma lucidum (Lingzhi or Reishi): A Medicinal Mushroom. In: Benzie IFF, Wachtel-Galor S, editors. Herbal Medicine: Biomolecular and Clinical Aspects. 2nd edition. Boca Raton (FL): CRC Press/Taylor & Francis; 2011. Chapter 9. Available from: https://www.ncbi.nlm.nih.gov/books/NBK92757/