Tending to Our Foragers Patch through Mycoremediation
It was an unseasonably cold, damp, and dreary May day — perfect weather for the mushrooms we’d be working with during our highly anticipated mycoremediation class.
A long-time mycophile (mushroom lover), I had spent years trying to learn my way around the mushroom kingdom, a bewildering community of organisms that didn’t operate by the clean-cut rules humans so love. Many fungi had recently undergone reclassification, as mycologists (those who study mushrooms) sought to recalibrate the parameters that would differentiate one family, genus and species from another. While fungi have been around a billion years, it was only in 1969 that they were designated as a kingdom separate from plants, so our nascent knowledge base of mushrooms is very much still evolving.
As a foodie forager, I’d mainly focused on edible species, but had read about the work underway to use mushrooms’ magic powers of infiltration and decomposition to remediate toxic sites, helping remove metals, chemicals, pesticides, herbicides and other pollutants from the land and sea. Mycologist and herbalist Jared Urchek came to teach us the basics of mycoremediation and apply it in two ways: installing oyster mushrooms to help clean the stream in our forager’s patch, and re-establishing a winecap mushroom bed to clean a patch of soil from an oil slick and rusty tools that previous occupants had buried nearby.
After addressing myriad questions on mushrooms and sharing fun facts about them (like shiitakes will fruit after getting smacked around because it simulates a tree falling — an ideal time to propagate), Jared put us to work creating mushroom waddles using a local strain of oyster mushroom (Pleurotus ostreatus).
Fungi take time to glom onto their host material (aka substrate) and establish networks of mycelium, which form the actual below-the-surface “body” of the organism. These unseen networks can cover thousands of acres, winning fungi the fair prize of the world’s largest living things. Each fungus can manifest in countless actual “cap and stem” mushrooms, the fruiting bodies that serve to multiply the species through spore dispersal. Not all fungi have that cap and stem, and they have various mechanisms for releasing their spores, but that’s a subject better treated in books that have already been written than an 800-word blog.
Those mycelial networks digest and share nutrients with trees (though some fungi also kill their hosts, so there’s that), and act as living glue, holding the soil together. They filter, decompose organic matter, and, to the point of today’s exercise, can digest manmade things too.
So, to our process: grind and pasteurize straw to kill any competing microorganisms and make it easier for the fungus to digest, then break up and mix in spawn pre-seeded with oysters, which we packed into plastic bags the size of a small toddler. Those new waddles would take time for the mycelium to populate, so we instead installed ready-to-go waddles Jared had prepped for us. We popped the straw-and-mycelium cylinders out of their plastic cocoons and burrito-ed them into old burlap coffee bags, plopping into the stream and secured with a few sticks and rocks.
In putting our mushroom burritos in the creek, Jared explained, we were deploying the permaculture concept of stacking functions: nature’s built-in ability to multitask. The oyster mushroom waddles could break down harmful compounds like the long-chain polymers in plastic, gobble up extra nitrogen from runoff, and send mushroom spores into the atmosphere, while the berms’ physical structures would help oxygenate, reduce sediment and filter water in the creek. Technically, food would also be produced, but given the mushroom’s tendency to hyperaccumulate metals in its fruiting bodies, didn’t seem like a clean food choice.
Meanwhile, there was a wine cap mushroom bed to be fed. This was a project of the Fox Haven Foragers class of 2020, and we could see from the decaying caps of the winecaps (Stropharia rugosoannulata aka garden giants, as their wine-colored caps can be as big as pizzas) that their labors had been fruitful. We infused the old bed with new mycelium, using the lasagna method of layering straw and woodchips and mixing in hungry chunks of young winecap spawn that, if all went well, would start to coat the straw and woodchips with its white tendrils of mycelium by the time we returned in June.
Jared shared with us a failed spawn project too, which had a slightly “off” odor compared to the happy spawn, which, depending on the nose, smelled like anise or almonds. It was a reminder that no matter how much you knew, there were always greater, uncontrollable forces at work. We would see next month whether our cooperative experiment with nature would take hold, but if nothing else we all learned much in the process.
Written by April Thompson, @prillytee on Instagram
April Thompson is a Washington, DC based writer, gardener, foodie and forager. Working as a freelance writer for more than 20 years, April has covered food, travel, sustainability, gardening, foraging and other subjects for dozens of publications, including her ongoing column in Natural Awakenings magazine. She has taught workshops on wild edible plants, fighting food waste and related topics for Knowledge Commons DC, Rooting DC and other organizations. She is a founding member of the Bruce Monroe Community Garden, a member of the Mycological Association of Washington, and an alum of the UDC Master Gardener program. She currently serves as Director of Marketing and Sales for Bloom, a recycled biosolids fertilizer developed by DC Water.