How to start
The first step to take when you get your log home is to put it in a shady spot either outside or indoors. I recommend that you keep your log outside, since they tend to do better there and they are easier to care for, and I won’t be able to troubleshoot problems with indoor cultivation. Still, indoor cultivation is an option for your mushroom log, though I will direct you to others for instructions on how to do that. For example, Lost Creek Mushroom Farm provides instructions on indoor cultivation, including directions on watering that are quite different from what I recommend for outdoor cultivation.
Care instructions for Outdoor Cultivation
There are a few basic things you need to know about, including where to keep your log, watering, fruiting, and resting.
Where to keep your log Store it in a spot where there is no direct sun, but where there is still some light. The location shouldn’t be too drafty – since this will dry out the log – and the log should have one end on the ground to absorb moisture. Flip the log over every month or two so that both ends get a chance to hydrate more. If you can store it among some plants or shrubs, that will help to retain moisture. A wicker basket may serve the same purpose. If you want to store your log under deciduous tree canopy, you will need to find a different location when the trees aren’t leafed out, or you can cover them in 80% shade cloth. I have shade cloth tarps for sale if you’d like a covering that will protect the logs from over-drying in partial or full sun. However you shade your log, make sure that there is space around the bark for the log to dry off. Without this space, you may inadvertently encourage mold to grow (more below).
Fruiting Mushrooms Your log is ready to fruit, as long as your temperatures are generally above 55 degrees. For most mushroom varieties, the logs will produce when spawn run is complete and the conditions are right though out the summer. Just keep and eye out for mushrooms so that you can harvest them before they sporulate (more on that later). Fruitings will tend to happen several days after a good rain. If you haven’t received rain for some time and would like to encourage the log to fruit, you may want water them with a maintenance watering or concentrated fruiting (see below).
Maintenance watering You can encourage additional fruitings by watering your log with a sprinkler or immersing it for an hour as often as once a week. The log may fruit a few mushrooms within a week or so after this watering.
Shocking logs for concentrated fruitings With enough regular watering, Shiitake mushrooms will fruit mushrooms every so often, but you also have the option of shocking your log to get a concentrated harvest. This is often called a force-fruiting. You can generally force-fruit logs between July (or when temps have gotten into the 70s and 80s for a few weeks) and late September.
Start by soaking your logs completely for 24 hours in cold non-chlorinated water. You can train a sprinkler on them or soak them in a tub or barrel. A five-gallon bucket works well for a 12” log. You shouldn’t use chlorinated water, but rain water or city water (such as in Minneapolis anyway) is good.
After soaking, put them back in a shady spot, ideally as upright as possible, since they will be easier to harvest that way. Cover the log with a paper bag or half-cover with a plastic bag or tarp. This covering will warm the logs a bit, and will retain moisture around the log. You should sprinkle water on the soil under the logs daily – until you see pins develop widely across the surface of the log. This is also a good time to pull off the bag. Pins are little brown bumps that should develop into mushrooms. If the pins start to dry out, you can resoak the log for 20 to 30 minutes or mist often to re-hydrate them.
Harvesting The mushrooms are ready to harvest when they have flattened out somewhat, but are still concave. This should happen within 6-10 days. In order to remove mushrooms from the logs, twist the base of the stem while pulling. If they get too mature, they will sporulate – which looks like a white dusty powder under the mushroom. These mushrooms are edible, but not as tasty.
Yields Mushroom harvests can vary significantly, but you should get between 2 and 3 oz. per foot of log per force-fruited flush. Even an ounce is enough for a small meal, but you may want a few larger logs to provide mushrooms for a family. You can count on a bit fewer mushrooms if you don’t choose to force-fruit your log. How long they keep producing depends in large part on the diameter of the log; larger diameter kits may keep producing mushrooms for many years, smaller ones for only a couple of years.
Resting after force-fruiting If you shock your logs – as you can do with many Shiitake strains – you will need to rest them for at least two months before the next force-fruiting. A metal tag is attached to this log with the name of the shiitake spawn. I generally attach some masking tape to the tag with the date of the last force-fruiting written there in permanent marker. Give it regular maintenance waterings during this time if you can, since it is recovering from the force-fruiting. After this, you can shock it again after another two months. After the first year, yields will diminish, but you should be able to force-fruit your shiitake logs for two years, with two force-fruitings per summer.
Winter Spawn run slows down and then stops in winter. This log won’t fruit under 55 degrees or so, but you will still need to protect your log from freezing winds – which will freeze-dry your log. The easiest way to protect it is to bring it into an unheated garage or shed. If you are going to leave it outside, the best way to do that is by covering it tightly with 80% shade fabric. But in that case, make sure to loosen the fabric or remove it when temperatures start to rise above 40 degrees – which is the temperature at which mold starts to flourish.
Trouble-shooting Pests Mold and other fungi are probably the greatest threats to your log. Your log ends may or may not have a thin white growth around the outside – near the bark. If it does this is probably mycelium. If this white growth is thicker, is growing in the center of the log end, or especially if it can be found along the length of the bark, you probably have a mold infestation. Mold can also be green or blue. Wiping off the mold won’t help your log, but they mold may not prevent fruitings. Give the log more room around it for the bark to breathe or move it to a breezier spot, and water a bit less often.
It is unlikely that you will find other fungi on this log, since it has already fruited shiitake successfully, but these are a few fungi that often compete with Shiitake. I have had the most difficulty with diatrype spp. – a fungus that will manifest itself in a raising of large blisters leaving dark raised areas. This isn’t contagious, but it may decrease the productivity of your log. Fawn and Honey mushrooms can sometimes be found on Shiitake logs, but they are both edible. The one to be most wary of is the Deadly Galerina (Galerina autumnalis), since it can be lethal. It is a small brown mushroom with tawny gills and a thin ring on its stalk.
In order to positively identify a shiitake mushroom, look at the underside of the cap. The white gills shouldn’t be continuous, but eroded or rough-edged (see illustration). If you still aren’t sure, ask an experienced shiitake grower or mycologist for help.
Most other pests are not much attracted to inoculated logs, except when they start to fruit mushrooms. Watch out for squirrels and rabbits, which you can fend off with bird netting or wire mesh. Slugs will also eat your mushrooms – especially those growing close to the ground. They can be deterred with some powdered lime sprinkled on the ground, or other controls.
Enjoying your harvests Mushroom cultivation is a lot of fun, and the results are tasty too. Shiitake mushrooms have a rich smoky flavor and meaty texture that recommend them for full-bodied soups or omelets, sumptuous pizzas, rice or pasta dishes. I often start by heating some butter or bacon drippings in a pan and cooking the sliced mushroom on medium-low heat until the mushrooms release a nutty fragrance. Generally I only cook the caps, but don’t throw away the stems; they are a rich addition to soup stock.
Until you can eat them, store mushrooms in a paper bag in the refrigerator. They will keep for between nine and fourteen days.
Drying mushrooms is a great way of extending the season, especially useful if you cultivate your mushrooms outdoors. Use a dehydrator or oven on a very low temperature with the door propped open until the whole or sliced mushroom caps are light and brittle. Usually this takes between 12 and 24 hours. To rehydrate, soak the mushrooms for at least an hour in just enough warm water to cover. If you can, toss the soaking water into your recipe too, since it absorbs some of the flavor of the mushrooms.
Shiitake mushrooms have many health benefits. Shiitakes boast of high levels of protein (18%), potassium, niacin and B vitamins, calcium, magnesium and phosphorus. They lower cholesterol, and they contain the antioxidant L-ergothioneine as well as compounds that strengthen the immune system. Shiitake may also reduce tumors and the side-effects of cancer treatments.
This shiitake mushroom kit was started on a log on our urban farms in south Minneapolis and Ham Lake. We use logs that were sustainably-harvested in Minnesota and Wisconsin. No fungicides are used by CTHM.
If you baby your logs a bit, you should get plenty of delicious mushrooms. Enjoy!
Contact Farmer Jeremy McAdams at 612-205-8599 or fill out the form below:
Cherry Tree House Mushrooms LLC, 827 15th St., Clayton, WI, 54004