Water, The Environment, & Mushroom Cultivation

David Arora titled his pocket field guide, “All That The Rain Promises and More.” The relationship between water and mushrooms is so direct that it’s an apt title for a book on the subject. Mycelium requires water to make a fruit body (mushroom), and mushrooms require humidity to release their spores. Growing a water intense crop in the desert requires us to be mindful of how, when, and why we grow mushrooms.

This is something I’ve thought about a lot. When I was growing as a hobby, I felt some responsibility to be smart with water use, although I was growing such small quantities that it didn’t weigh too heavily on my conscience. Now that I am running a business and distributing grow kits to others, I feel an increased level of environmental responsibility. While some amount of income is necessary for me to be able to dedicate as much time as I do (bills to pay), profit is not a justification for doing harm. This is one of my core beliefs, and I try to live accordingly.

With all of this in mind, there are several tangible steps that I have taken to make Fungal Focus environmentally sustainable, as well as some bigger picture ideas that are equally, if not more, important.

Almost all of the water that I use to grow mushrooms, including the water used to wash out reusable mason jars, serves at least two purposes. Pasteurization water is cooled and used to water the plants in my garden. Water from washing things contains biodegradable soap, and is used to water the lawn. Using this water on the mushrooms directly would probably lead to a contamination issue, but I have had no problems using it on the plants.

Creating humidity for the fruit bodies is another opportunity to creatively meet the challenges of our climate. My mushrooms are watered by patio misters on a timer. Underneath the mushroom shelves, I have apple tree seedlings in pots that catch some of the excess water.

Spent mushroom cultivation substrate is used to mulch the garden beds. I estimate that I have to water the gardens about 1/5 as often as I have to water bare soil. The mulching helps keep the soil cool and prevents water from evaporating as quickly. If it rains, the mushrooms usually fruit. This extra material also helps with weed suppression.

In December, my neighbor was cutting down a live Cottonwood tree. I snagged some wood, and with the help of friends, we inoculated it with phoenix oyster mycelium. These logs are the basis of my raised garden beds. While log cultivation can be tricky in Utah, I am hopeful that they will fruit. If not, they look cool and they didn’t end up at the dump.

The buckets that we grow our oyster mushroom kits in are food grade buckets repurposed from an ice cream shop. While oyster mushrooms aren’t known for eating plastic, they do absorb many of the chemicals in their environment, so growing them on recycled high quality plastic is ideal. These buckets can also be washed and reused.

While oyster mushrooms are known for growing on a variety of substrates, I have had the best luck growing them on straw. Because I am selling these, there is a reasonable expectation that they will fruit. For this reason, the kits that are distributed in classes and CSAs are grown on straw and roughly 10% recycled paper bags from the grocery store. The ink on these paper bags is vegetable based. We also acquired organic straw for the 2022 season. At home, I experiment growing on various types of recycled organic matter, including coffee, cardboard, spent grains from breweries, and so on. Moving toward more recycled material is on our radar for the future.

Lastly, I whole heartedly believe that understanding how fungi, plants, and carbon dioxide interact is an imperative step toward addressing the climate crisis. Any land management or farming policies created without this foundational knowledge will fall short. With that in mind, any information or appreciation for fungi that I can help spread is a small step toward this goal. If growing mushrooms is what sparks someone’s curiosity into these more complex issues, then it is well worth the water that it takes to grow them.

For more on how to garden with fungi, check out our Fungi From Forest to Farm workshop.

For more on mushroom cultivation, check out Mycology For Beginners or any of our upcoming Mushroom Cultivation or Fruiting & Cooking Oyster Mushrooms classes.

For more on fungi, plants, and carbon dioxide, check out Fungi Inside & Out.