Not many mushrooms inspire the sort of fervor that morels do. Perhaps it's precisely because of their elusive nature that they're so prized. Let's take a closer look at the features of this shroom that make us swoon.
Description: Morels are unlike most of our common mushrooms. They lack gills, pores, or teeth to drop spores and instead are completely hollow with craggy or spongelike surfaces which shoot out spores like cannons. Their overall shape is more or less oval or conical with an irregularly pitted cap which varies in color from yellow to gray to black. Stems may be swollen at the base, hollow and whitish to cream colored. Their flesh is firm but brittle. Size and spore print color varies by specific species.
All morels are in the genus Morchella and the individual species vary both in distribution and ecology, though they may be difficult to distinguish based on appearance alone. We're still learning a lot about the taxonomic breakdown of this family, with the help of citizen science initiatives and DNA barcoding. Loosely, true morels are broken down into two main groups: yellow morels of the Morchella esculenta clade and black morels of the Morchella elata clade. Within the black morels, there's a subset called burn morels with very specific ecological dynamics and quite a big fan following. Black morels are so-called because their often vertically oriented ridges darken with age.
A microscopic look at the spores housed within sac-like structures called asci in the tissue of a morel.
Ecology: Whereas oyster mushrooms can and will grow nearly anywhere, morels are infamously particular about the conditions they prefer, which makes them elusive for foraging and difficult to replicate for cultivation. As mentioned above, there's variation between species and their preferences.
Even the niche they inhabit is hard to pin down, and morels seem to move between saprobic and mycorrhizal phases in their life cycle. We don't fully understand this dynamic, but that means they can be both decomposers and have a complex relationship to a plant partner - an interesting duality to hold! That being said, they only grow terrestrially or on the ground. So you won't find them on the trunks of trees.
East of the Rocky Mountains, we mostly encounter yellow morels, sometimes black morels. But on the West Coast, where forest fires ravage conifer forests, burn morels can be abundant.
First, let's look at what environments yellow morels prefer. Knowing your trees can go a long way in helping you find the mushrooms you're looking for. The yellow morels associate with: dead or dying elms, living ash, tulip poplar, sycamore, apple and sometimes even pine. These tree species commonly grow in fertile or sandy soils of floodplains, which coincides with the idea that yellow morels prefer riparian habitats. Once soil temperatures are consistently 45-50 degrees, a heavy rain can trigger yellow morels to fruit.
Here in Maine, morels are quite rare in part due to our acidic soils and the species composition of our boreal forest. Though they evade us in wooded habitats, we've seen morels pop up in some pretty unexpected places like between the sidewalk and asphalt of a driveway, just down the street from our facility in Westbrook!
Black morels in the Midwest and Eastern US will appear before yellow morels, often in the warm and wet spells of early spring. Their tree associations are with ash, black cherry, aspens, cottonwood, and tulip poplar. Dark hues make them hard to spot among the leaf litter. In the prairie lands west of the Appalachians, morels are found in fields far from any potential tree partner, further puzzling foragers.
Moving west, morel ecologies become more reliant on disturbance than anything else, where the predominant morel encountered is the notorious burn morel. These special mushrooms occur in forests dominated by conifers including pitch pine, jack pine, spruce, and fir in the spring and summer after fires have charred the earth the previous season. It seems light or moderate fires are preferable to severe ones, and the appearance of morels gives some perspective about the destruction left in their wake. Morels might also appear after other disturbance events, like heavy logging, another reminder that humans play a role in shaping ecology, too.
In terms of timing, temperature requirements are similar to yellow morels but a few other factors are at play. Areas that have been burned may lack their normal canopy cover, allowing sun to warm soil faster. That means that burned areas with higher elevation may begin to fruit ahead of lower or more southern locales. Attention to phenology, or the study of seasonality, helps to hone in on timing. Plant emergence and flowering, animal mating, and bird songs all can piece together the puzzle of when is right to start looking.
Difficulty for Outdoor Cultivation: Experimental. We are still learning so much about the complex dynamics of these mushrooms but some site-specific successes keep the hope alive that with collective trial and error we'll discover how to better support the growth of morels.
Our Culture: Since successfully growing morels is still experimental, we'll give you as much information as we can to help steer you in the right direction. Knowing more about the particular culture we use can offer some clues about how to replicate the environment it naturally fruited in. Morel cultures or spawn acquired from other sources, of other species, may need different treatments.
The culture we use to make morel sawdust spawn was cloned from a wild burn-site morel found in a pine stand in New Hampshire in late spring after fall fires the previous season. The forest fruited where the fire penetrated deeper below the duff layer, smoldering into sandy mineral soil. In terms of timeline, these morels appeared later than the black and even yellow morels more common to the New England landscape. Since it was a dry spring, it's more likely that the fire disturbance followed by a freeze period and appropriate rise in temperature was the trigger for producing these rare specimens.
To date, we have yet to find documentation of burn morels found on the East Coast in any scientific literature. A fact emphasized by guides which define burn morels as occurring west of the Rocky Mountains. That makes this particular specimen curious and unique from a taxonomic perspective. We'll keep you posted as we learn more about this species and how it fits into the larger Morchella picture.
Potential Growing Methods: So far, the best approach to cultivating morels is in beds and perhaps with some more difficulty in trays. Intrepid growers can attempt to replicate the original growing conditions of our burn morel by using burned substrate as a non-nutritive layer, which encourages the morel mycelium to spread deeper into the soil to seek nutrients. More on the why this matters and tips on getting set up are followed below.
Mycelium Formation: A better understanding of morel life cycles has vastly improved our methods for cultivation. Comparatively, morel spores germinate more quickly and mycelium grows faster than most white rot fungi. For most fungi we cultivate, that mycelium continues to grow until it runs out of space, food, or another environmental factor triggers it to fruit. However, morels require another step: the formation of a sclerotia or a dense cluster of mycelium meant to store nutrients.
Sclerotia are formed in response to an environmental stressor and we can encourage them with a process called backstreaming, described by mycologist Tom Volk. In it, the morel mycelium is cultivated between two distinct substrates, a nutritive and non-nutritive layer. By placing the culture on the nutrient deprived side, the mycelium must travel in search of food to transfer back to the other side. That stress seems to be enough to produce sclerotia within a week or two. Alternatively, the culture may be placed between the two substrates, in a sort of liminal space. In this case, the mycelium attempts to colonize both at once, hastening the sclerotia formation. Interestingly, where the sclerotia end up is typically within the nutritionally scarce substrate - a mycelial storage unit in a 'food desert'.
If you've received a bag of morel spawn from us, it may look like not much is happening. We're used to seeing the thick white mycelium of oyster mushrooms. Morels mycelium tends to be lighter and closer to an orange or ochre color, making it a little harder to see on sawdust. If you look closely, though, you will likely find an orange knot of mycelium - a sclerotia.
Site: Whenever possible, it's a good idea to install your morel beds near trees we know them to associate with, in shade, or in a preferred soil type. For our culture that would mean sandy or mineral soils around pines or a mixed conifer stand. Though morels don't form mycorrhizal relationships in the same way we know other fungi do, they may rely on the microbiome created in a particular host plant's rhizosphere. It's certainly worth testing out different tree associations on the same site for comparison and there's potential for planting trees into an installation or attempting to inoculate tree roots. If you lack tree cover, it can be helpful to use shade cloth or some sort of structure to limit light exposure.
Substrate: Substrate formulation should take into account the dynamics between a nutritive and non-nutritive layer to facilitate proper sclerotia formation. With that in mind, there's a lot of room for testing out different combinations. Some ideas for a nutritive layer include: sawdust, wood chips, or agricultural wastes amended with soy hulls, wheat bran, cooked grains, or even just a rich soil or compost. For the non-nutritive layer you can try: sand, peat moss, coco coir, sterilized soil, wood ash, or other burned organic materials.
We know that morels tend to prefer mildly alkaline substrates, so wood ash may serve as a medium both to replicate the original growing conditions and to adjust the pH of your grow. Otherwise, you can use hydrated lime if you'd like to add some alkalinity.
It seems best to either inoculate the non-nutritive layer or spread the spawn out as a layer unto itself above it to create the backstreaming necessary for sclerotia formation. To prevent pests from burrowing, add some leafy debris, chicken wire, or some sort of fence around the bed.
Temperature: To the best of our knowledge, morels require a freezing period, thaw and draining of their soil, followed by a rise in soil temperatures to about 50 degrees F. This cycle mimics the temperate transition from fall through winter and spring. It's unclear if morels may grow in more tropical climates.
Fruiting Information: While we don't know exactly what may cause a bed to fruit, it may be helpful for it to go through a freeze and thaw cycle as it would in nature. Some techniques described elsewhere also suggest flooding the bed ahead of winter dormancy.
Harvesting: Mature morels are often determined by their size and the color of their cap, especially of the ridges. Yellow morels when young can appear gray, developing a richer yellow or light hue as they age and light ridges. Black morels on the other hand will darken nearly to black along their ridges. Besides Morchella diminutiva, a rather small morel, most yellow and black morels will be medium sized or 3-6 inches tall. You can pluck or cut the mushroom at it's base, taking care not to disturb the soil too much. Either style will leave the mycelium unharmed.
Medicinal Qualities: Morels boast a high protein content are rich in minerals and B vitamins. Additionally, they're being researched for their potential to support the immune system, their anti-oxidative, anti-inflammatory, and anti-tumor properties. (1)
Cooking: Morels are toxic when they're eaten raw, and can cause gastric upset. So, it's very important that they're cooked thoroughly to avoid illness. Like any mushroom, it's possible for some individuals to have an adverse reaction or allergy to eating them, so we encourage you to only eat a small amount - a couple bites - the first time you try them to see how you feel.
All that considered, morels are a highly prized edible with a rich and distinct flavor. To let them fully shine, we like to prepare them simply by sauteeing them on low to medium heat in a fat with some other spring alliums if they're on hand. Pair with your favorite pasta or some fresh caught fish. Preserving morels is easy and they dehydrate well, so if you find a honey pot, you can really stretch our your enjoyment of this special shroom.