Project synopsis: In this project we worked on rebuilding soil with Wine Cap Stropharia mushrooms- or, more accurately, Wine Cap Stropharia mycelium. This organism has the incredible power to decompose woody material and leave behind a nice, loamy soil. This project put that power to the test.
Linked on the upper right side of the page you'll find the video series for this project. The videos provide a more visual tutorial to the process that may be helpful if you plan to undertake a similar project.
The Project Inspiration
A scary, but maybe little known fact, is that we are going through topsoil approximately 10 times faster than it can naturally replenish. In a report put forward by the UN Food and Agriculture Organization this translates to approximately 50 years left of soil rich enough to support agriculture practices as they stand now. As a disclaimer- we are by no means experts on soil science, so if you're looking for more information on this particular subject we would highly recommend documentaries such as "Kiss the Ground" that focus on implementing regenerative agriculture practices and improving soil health for sustainable use. Either way, after hearing this factoid, we set out on a project of our own to try to rebuild soil with fungi.
The Backstory
In June of 2022 one of our team members decided to turn their entire side yard into one, massive Wine Cap Stropharia bed to see if Wine Cap mycelium could convert wood chips into a plantable material. While the house was undergoing some renovations, all of the excess housing material was placed in the side yard. When the time came to clean up the material the contractors brought in some big machinery and, unfortunately it took several inches of the soil along with the materials meant to be removed. This left a scarred and tilted yard-scape. The goal of this project was to rebuild any of the lost soil using easily available resources. In some places in the yard we were looking to build back 8 inches of material.
The Process
While the logical option in this scenario would have been to just buy in a load of topsoil to even the yard out and then plant it, that wouldn't have been in the spirit of using fungi! Our approach instead went something more like this:
- Cover the yard in cardboard
Why this step? The yard as it existed was full of weedy grasses. A far cry from a lawn, but also not native grasses worth fostering. The cardboard helps stifle out the weeds, allowing the wine cap to break down the bed materials without interference. Holes were poked into the cardboard at random intervals to make sure that water from rain wouldn't pool and drown the mycelium.
- Add Wine Cap Stropharia Spawn
In this case spawn was sprinkled directly on the cardboard. If you do this make sure that the cardboard is soaked prior to spawn placement to ensure that dry cardboard doesn't leech the moisture away from the spawn. Labor time can be greatly reduced if you either set up a sprinkler to soak the cardboard or strategically lay the cardboard out right before the weather service calls for rain. The project area covered about 920 sq ft. When using Wine Cap mycelium strictly for mushroom production we recommend using one bag per 25 sq ft BUT if your main goal isn't to see mushrooms as quickly as possible you can certainly stretch the square feet per bag. In this project we used 20 bags, which translates to a using one bag per just under 50 sq ft.
- Cover the Area with Wood Chips
What type of chips? Just about anything will do as long as it is not solely a coniferous chip. Some conifer, or softwood chip, is fine but we recommend no more than 25% of a mix for a project like this. We used two pickup truck loads of a mixed chip we picked up from city tree trimmers. *Tip: Often times you can find tree trimmers that are looking to offload their chips to avoid dumping them in a landfill! At the deepest point the wood chip layer was 8 inches in depth. We added some more spawn to these deep areas in hopes that the mycelium would colonize and digest the wood chips faster than areas of shallower wood chip depth.
- Wait
With the amount of wood chips that the wine cap mycelium needs to digest, this process will take awhile. Estimated duration of digestion at the time of plant was 2-3 years. The area will likely start producing mushrooms by the spring of the following year (spring of 2023), but the decomposing of wood chips into a plantable organic matter will take significantly longer.
One Year Later...
Fast forward to spring of 2023. At this time we started to see some Wine Cap mushrooms appear which was a nice little bonus, but more importantly, digging into the wood chips we were able to see a lot of thready white material- wine cap mycelium. This meant that the Wine Cap was well established and digesting the wood chips. The decomposition was obvious when comparing the very top layer which was too dry for the mycelium and had very little decomposition to the bottom layer where the wood chips were starting to break down into smaller and smaller sections (compare figures 6 & 7). Furthermore, if we dug deeper we found that the cardboard laid down the previous summer was all but degraded where it had direct contact the Wine Cap mycelium. The wood chips did settle over winter so at this time we added more to continue our efforts in leveling out the yard.
Final Project Stages
By the Fall of 2023, it was time to turn the wood chips and see what was underneath the top layer. While it would have likely been better to let the Wine Cap work for one more year, there also comes a time when you will be exceedingly sick of walking across wood chips in your yard.
Turning was necessary as the top layer does dry out in the sun, leaving a half inch or so of wood chips undigested. While we could have just raked the wood chip layer away, active mycelium still remains and will continue to digest existing wood chips once they are turned under and no longer being continuously dried out by the sun. After turning the chips, a beautiful loamy soil was exposed - the result of two seasons of Wine Cap mycelium working its magic.
Finally, the soil was seeded. Seeding the soil in October of 2023 of course led to some challenges with the upcoming winter, but to our pleasant surprise, the seed took well and by August of 2024 the yard was sporting a nice green jacket. While there are still locations (particularly along the fence line) where the composition of wood chips remains high and grass hasn't grown yet, it's only a matter of time before the Wine Cap mycelium finishes its job there as well.
The New Soil
The most rewarding aspect of the project was the noticeable difference in soil quality. Along the side of the house where the soil was highest and there was little to no Wine Cap, the soil remained more sandy, while the soil from the center of the yard and along the fence-line where the Wine Cap bed was deepest, the soil has a nice dark color to it with a noticeably improved soil structure.
A project such as this does take commitment, but if you have a space you're looking to remediate and build soil and have ample wood chips we can now say with confidence that soil building with Wine Cap mycelium is certainly a solid option.
