Growing Backyard Mushrooms
Written onJune 01 , 2011
Even for the most adventurous gardeners and avid wild mushroom foragers, the idea of growing one’s own gourmet mushrooms may seem mysterious. But there are a number of methods that gardeners and farmers use to incorporate gourmet mushrooms into their landscapes, and these methods are fairly easy for anyone to try at home. Visiting a mushroom farm or attending a hands-on workshop is the best place to start, and below are some simple secrets of backyard mushroom cultivation to serve as an introduction.
My first attempts at growing gourmet mushrooms were while studying sustainable agriculture at UC Santa Cruz. After joining some experts on forays into the forest and attending a workshop, I incorporated shiitake, oyster, and native choice edibles into a permaculture demonstration garden I installed on campus. I went on to grow Grey Dove oyster mushrooms for local restaurants and markets in Santa Cruz. That was six years ago, and since moving back home to New England I’ve been growing a few of my favorite mushrooms at home and sharing my experience with anyone who wants to learn.
Mushrooms such as shiitake and oyster are simply the fruit of much larger fungal organisms. The bulk of the fungal body is made up of a network of threadlike cells called mycelium, which run through a medium, such as dead wood or soil. This mycelial network can be likened to a root system and can be seen as white fuzz on the inside of logs, or under duff on the forest floor. The mycelial networks of fungi play a crucial role in natural ecosystems, helping break down plant materials and returning them to plants as the nutrient-rich organic matter that feeds the regeneration of plant life.
For the eager mushroom gardener, understanding what types of materials, or substrates, your favorite gourmet mushrooms grow on is very important. Shiitake, a favorite for many of us, grows on fresh wood and is selective about which kinds of wood it will grow on. Portabello mushrooms, on the other hand, grow on compost and manure. Oyster mushrooms are more versatile, growing on a wide range of materials, like many kinds of wood, straw, cotton waste, spent brewers grains, and coffee grounds. The chanterelle, a choice edible for gourmet cuisine, grows only in a symbiotic relationship with the roots of a living tree.
Let’s Get Growing!
If you’re eager to try growing gourmet mushrooms at home, start by spending some time surveying your home for the perfect place. Find spots in your yard that have shade, dappled light, and a moist microclimate where they are protected from the evaporative forces of wind and sun. Think about where you observe mushrooms in natural ecosystems. Although we often associate mushrooms with darkness, a bit of of light is important; a brief pass of sunlight over a mushroom patch aids in fruiting, as a moment of evaporation wicks water upward.
Although fungi generally reproduce via spores in natural ecosystems, most mushroom cultivation is done via spawn. Spawn refers to any material that is impregnated with mycelium. Often spawn is myceliated grains, sawdust, or pieces of wooden dowels and can be ordered from a number of sources. The substrate that the desired mushroom will grow on is embedded with myceliated spawn, and then given the perfect conditions to grow. The temperature, moisture levels, and ratio of spawn to substrate will affect the time it takes for mycelium from the spawn to colonize the material. This can take between 6 weeks and 12 months, depending on the species. Be patient, though; once the mycelium has fully colonized a material it begins a fruiting cycle, which lasts until the material is exhausted. Fruiting often occurs roughly a week after a rain event, natural or simulated.
Nicholas Laskovski of Dana Forest Farm in Waitsfield cultivates certified organic, forest-grown shiitake mushrooms on cut sugar maple logs at his family farm. He harvests a quarter pound per log twice a year, over a span of 3–8 years. At times, Nicholas says, he’s harvested multiple pounds from a log in a single fruiting event. “[To stimulate fruiting] I give the logs a cold water bath for 24 hours after they’ve been inoculated and sitting in the forest for about one year. Because of this trait, it allows me to rotate the logs in a manner that gives me perpetual fruiting over the summer.” Nick sells his mushrooms at his farm and to local restaurants in the Mad River Valley (www.facebook.com/DanaForestFarm).
Basic Backyard Methods
The Mushroom Patch
As with many recipes, these are just suggested ingredients in suggested amounts. Ultimately you will be creating lasagna layers of whatever cardboard, wood chips, sawdust, or other substrate you have nearby with mycelium mixed in, in the right proportion. Mushroom patches can be layered over garden beds with holes for plants to achieve a companion-planting scenario.
1. First clear your chosen site of existing debris, which may be hosting other fungi. Let’s imagine it’s a 3 x 6 foot space.
2. Lay cardboard over the site and cover with moist sawdust or wood chips that are 1 to 2 inches thick.
3. Spread an approximately 2-quart bag of sawdust spawn.
4. Lay bits of ripped cardboard randomly, with the corrugation facing the sawdust spawn. (The corrugation is easily exposed if the cardboard is soaked and pulled apart.)
5. More sawdust or wood chips 1/2 to 2 inches thick.
6. More cardboard—with a goal of 80–90 percent coverage.
7. More sawdust/wood chips—total coverage if possible.
8. Add water.
This is the best method for beginners and is best done with a group of people, or at a workshop.
1. Find logs 4 to 8 inches in diameter that the desired mushroom is known to grow on, and cut them to the desired length—1 to 2 feet, or longer for stacking.
2. Check the ends of the log for white clouds to be sure the logs are not colonized by another mycelium yet.
3. Drill holes across the surface at roughly 5-inch spacing. I recommend drilling the holes deeper than the length of the dowels—this will give the mycelium a little “cave” to colonize. A 5/16 inch bit should be what you need.
4. Insert inoculated dowels (a mallet is useful) and seal with wax. Optionally, log ends may be sealed with wax as well. The wax will keep moisture in, prevent other fungi from colonizing, and keep bugs from eating the mycelium.
5. Place logs in a moist location with dappled shade. Propping them on a pallet or rock may prevent competition from soil microbes—especially for shiitake. If you have inoculated a log in the winter, keep it in a warm place inside so that the mycelium will continue to colonize the log, and then place it outside in the spring. It is very important that the log remain moist for 8 to 12 weeks so that the mycelium can colonize it; the most common reason for failure is the log becoming too dry. Maintaining a balanced moisture environment for the log is important. If a log becomes too waterlogged, the fungi may also fail. I suggest placing it in a loosely open plastic bag near your shower, or spraying it frequently.
6. Wait 6 months to 2 years, depending on the variety of mushroom and type of wood used for fruit. You will see white clouds on the log ends when they are colonized. Soaking logs in water for 24 hours may induce fruiting.
Collecting Local Cultures
If you know how to identify wild mushrooms and you feel comfortable with the basic methods I’ve described, I encourage you to research what they like to grow on, to collect local cultures, and then to grow them in your home landscape. Maitake, reishi, oyster, morel, and pheasantback mushrooms grow in Vermont forests.
When you harvest a mushroom, pull the stem butt along with it—this is the base of the mushroom stem where it connects to the mycelium. Cover the harvested area with fresh mulch to protect and feed the mycelial network. Cut the butt from the mushroom body and place it in a bag with some moist sawdust or mulch to keep it from drying out. You should be able to see the mycelium at the base of the stem butt, which can be used to inoculate substrates elsewhere.
Alissa recommends the following resources:
Definitive Texts of Mushroom Cultivation
Growing Gourmet and Medicinal Mushrooms, by Paul Stamets
The Mushroom Cultivator: a practical guide to growing mushrooms at home, by Paul Stamets and J.S. Chilton
On Mycological Rescue of the Planet
Mycelium Running: How mushrooms can save the world, by Paul Stamets
Mushroom Identification Guides
Mushrooms Demystified, by David Aurora
National Audubon Society Field Guide to
North American Mushrooms, by Gary Lincoff
Sourcing Mushroom Products
Wichland Woods: www.wichlandwoods.com
Fungi Perfecti: www.fungi.com
Field and Forest Products: www.fieldforest.net
A Few Backyard Favorites
Get a positive identification on a mushroom before you eat or propagate it, please! As the old adage goes, “There are old mushroom hunters, and there are bold mushroom hunters, but there are no old, bold mushroom hunters.”
Oyster, Pleaurotus ostreatus
Usually a white or cream-colored fan with gills that run from under the cap, down the stem, generally clustered. Reduces cholesterol, inhibits tumors.
Elm oyster, Hypsizygus ulmarius
Grows to look like an oyster mushroom, often quite large and rare in the wild. Usually grows singly, sometimes with one or two others.
King Stropharia, Stropharia rugoso annulata
Often large, up to five pounds, brown-burgundy colored caps with brown gills and a white stem. Rhizomorphic and able to thrive in microbially rich conditions—well adapted to disturbance and grasses. Active against coliforms.
Shiitake, Lentinula edodes
Nutritious and prized medicinal mushroom—anti-tumor, antiviral, immune system stimulant. Brown cap with white gills and white/creamy stem, bruises brown.