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 sponge-like 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. The 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.

Fig. A is a microscopic look at the spores housed within sac-like structures called asci in the tissue of a morel mushroom.

Fig. A

Gyromitra esculenta, a False Morel

While morels are generally easy to identify with their unique physical characteristics outlined above, there are a number of lookalikes that fruit at the same time and some can be toxic if consumed without correct preparation. True morels are usually more cratered, or pitted, vs. false morels which are finned, wrinkled, or bubbly-looking. The “False Morel” is a general term encompassing a number of species in the genera Gyromitra, Verpa, Hellvella, and Disciotis, with species in the Gyromitra and Verpa groups being the most often misidentified varieties. Some, like bell morel (Verpa conica) and wrinkled thimble-cap (Verpa bohemica) appear very similar to true morels and can even be prepared in the same manner. Others like Gyromitra esculenta are more dangerous and contain the toxin and carcinogen gyromitrin, a component of rocket fuel, but can be consumed if this chemical is removed prior to ingestion using the right cooking methods. While it is not too difficult to distinguish between true and false morels, we encourage thorough identification before consuming any mushroom.

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. 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 supports the idea that yellow morels prefer riparian habitats (wetlands). Once soil temperatures are consistently 45-50 degrees F, 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 old facility in Westbrook!

Black morels in the Midwest and Eastern United States 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.

A few years ago, we were able to visit Jeremy Faber of Foraged and Found to learn about hunting burn morels.

Morel mushroom cultivation is experimental and we recommend it to those with previous experience and skill growing outdoors. We are still learning so much about the complex dynamics of these mushrooms but some site-specific successes keep us inspired to continue discovering how to better support these beloved fungi.

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.

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'.

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.