Fungi are everywhere. They pop up throughout our environments, appearing as mold on fruit, yeast in beer, and in our yards. Not quite a plant, and not quite an animal – they are a kingdom all their own.

It hasn’t always been that way. Historically, naturalists classified fungi as a type of mysterious chlorophyll lacking plant sometimes called thallophytes. It wasn’t until 1969 that scientists separated fungi into a kingdom separate from plants, based on evolutionary and biological observations. The advent of DNA sequencing more recently revealed that the fungal kingdom is more closely related to animals than plants! Mycology, as we know it today, is a very young science. Many of the terms mycologists still use today to describe fungi are vestiges of their residency in the Kingdom Plantae.

Fungi are eukaryotic organisms, meaning they are made up of cells whose DNA is contained in a nucleus bound by a membrane. So are plants and animals, but fungi diverge in some distinct ways. They do not photosynthesize like plants, so they cannot produce their own food. Instead, fungi are heterotrophs meaning they obtain nutrients from other organic material, often other organisms. Animals share this trait. However, animals ingest and then digest their food. Fungi, on the other hand, secrete digestive enzymes into their environment and then absorb the nutrients released.

While all flowering plants grow from seeds, mushrooms grow from either spores or tissue culture. Every mushroom releases thousands of spores into its environment, each carrying genetics unique to that spore. So, growing from spores is akin to planting a bunch of apple seeds – it can be unpredictable, and none will be identical to its “parent.”

The mushrooms we are most familiar with, your classic cap and stem mushrooms, are members of the phylum Basidiomycota. All mushrooms in this group, including jelly fungi, puffballs, and porcini, produce their spores outside of club-like cells called basidia. Other, perhaps stranger looking mushrooms are in the phylum Ascomycota. Think morels, corals, and cups! Ascomycetes produce their spores internally, within sac-like cells called asci.

When one of these spores lands in the right environment, it’ll germinate and send out a small filamentous thread called a hypha. These fungi grow from the tip of the hypha, a sort of bud of potential, extending forward in response to outside stimuli. While scientists don’t totally understand this process, the dominant theory is that an organelle called the Spitzenkorper organizes and directs the growth patterns in pulses, like a microscopic architect.

Famous and funny mycologist David Arora titled a book All That the Rain Promises and More. Truly, a heavy rainfall is often a cue to go foraging for mushrooms. Fungi growing outside take cues from their environment to begin forming mushrooms. Changes in humidity, temperature, and moisture are major determining factors for when mushrooms grow, and each species of mushrooms has a particular preference. Just as tomatoes in Maine don’t set fruit until June, mushrooms also have a sort of biological clock. As I write this in mid-summer, Chanterelles are just peeking out from leaf litter, orange beacons in the forest. After almost two months of drought and a few solid thunderstorms, the woods are alive again with fungi.

Mushrooms grown indoors lack the same environmental exposure as wild mushrooms or mushrooms in a garden. Typically grown in containers, these fungi concentrate their energy on colonizing their substrate until it’s fully engulfed in mycelium. Once complete, the fungi runs out of food and space to keep growing. If we recall the fungal life cycle, these are both situations that trigger fruiting. Depending on the set-up, a grower may put their container into a specialized room or space with temperature and humidity controls to dial in for that specific species. On a smaller scale, martha tents and monotubs can help a home grower achieve the right conditions. Sometimes, the fungi can’t wait and burst through their container. It’s incredible how strong mycelium is!

Generally, mushrooms love to grow in moist, humid, shady areas, but they can also pop up in some pretty unexpected places. For a few years we found Morels growing out of cracks in the sidewalk near our Westbrook facility! If we know a little more about what type of food the fungi consume and what function it plays in its environment, we’ll gain insight into where mushrooms grow.

Almost all of the fungi we can cultivate are saprophytic, meaning they’re decomposers. Some specialize in digesting woody material – the only organism capable of this feat! Others break down nitrogen-rich substrates like manure. Mycorrhizal mushrooms are a bit more complex. These types of fungi partner with a plant host, exchanging scavenged nutrients in the soil for sugars. Many are very specific to their host, though a few are considered generalists.

Matsutake, a mushroom highly coveted in Japan and a major topic of the book The Mushroom Hunter, is rare to find on the East Coast. Preferring a specific type of clay soil common to colder climates, and a select few conifers (eastern hemlock, red pine, jack pine), this mushroom is a specialist. Finding mycorrhizal fungi can be more challenging, requiring some skill with plant identification and mushroom ID, though you can certainly stumble upon honey pots! Personally, we find more joy in finding just the right ecology for a particular mushroom, for all the variables to fall in line at the right time.  

Growing outside can be incredibly fruitful, too! If you have any wooded land, lots of perennial plant cover, or evergreen shrubs or trees, you most likely have a suitable environment for outdoor mushroom beds or logs.

Mushrooms can also be easily incorporated into your garden, benefitting the soil and surrounding plants. You can tuck them into mulch in vegetable beds or paths, inoculate containers or bales, or even bury blocks. Any way you choose to grow, you want to make sure the fungi stay moist, especially if there’s a drought, and that they don’t receive too much direct

Starting with species that are sure to grow, like Blue Oyster (Pleurotus spp.), Wine Cap (Stropharia rugosoannulata), and Shiitake (Lentinula edodes) is the best way to cut your teeth and keep your mushroom growing morale high.

As you learn more, feel free to experiment, and don’t hesitate to us if you’ve got questions or to share your mycological journey!