Ok, let’s review. So far, we know the railroad ties decomposing in my yard are really bad news for the soil in terms of leaching toxic pollutants. We also know that the Elm Oyster mushroom is known to be a great mycoremediator for wood preservatives such as creosote.
So now we have to figure out how to get Elm Oyster mushrooms to grow in the area where the railroad ties were removed.
Like I mentioned in my last post, Elm Oysters are not a terribly fussy mushroom, and we are in an ideal mushroom climate here in the Pacific NW (most of the time–we all know the weather has been a little weird lately, so fingers crossed!). The one thing about our location that is a little less than ideal is that it is getting full sunlight, and this mushroom prefers shade. However, I’m told that’s an easy fix with a makeshift tent once the baby mushrooms start budding (if we get that far!).
I decided to go with the simplest substrate of all for the mushroom to feed on–straw. It’s cheap and I can pick it up anytime. I’m not dependent on waiting for just the right kind of fresh wood chips from tree service companies.
Part of the idea here is that you want to be able to get started at the same time you plant your vegetable garden so that you get as many fruitings of mushrooms as possible throughout the season (app. April-late September). The mushrooms will have eaten through all of the straw by that time so you get the maximum benefit from your work. We can test the soil again at the end of September or whenever things die down.
I cobbled together a summary of 11 steps (below) by watching some online videos on creating outdoor mushroom gardens, calling some mushroom organizations with specific questions about the Elm Oyster mushroom and about mycoremediation projects as opposed to gardening projects, reading a ton of material both online and in Paul Stamets’ Mycelium Running: How Mushrooms Can Help Save the World.
Setting up the Elm Oyster Site
1.) Soak the straw in a waterproof container for 5-7 days first to semi sterilize it; nearly all the aerobic spores/bacteria die off during the soak, and the anaerobic spores/bacteria die off once the straw is drained
2.) Meanwhile, prepare the site by clearing any existing wood chips, digging a shallow hole, removing any other weeds, etc.
3.) When site is ready/straw is drained, lay cardboard over site
4.) Cover with 2″ of the straw mixed with a small amount of your contaminated soil (app. 20-25% soil)
5.) Put half your mushroom spawn/sawdust mixture over the straw/soil layer (this can be purchased online from 100th Monkey Mushroom Farm)
6.) Cover with another layer of straw/soil
7.) Place the other half of your mushroom spawn/sawdust mix over the straw/soil mix
8.) Top with a final 2″ of straw/soil
9.) Cover with a tarp over entire area
10.) Wait 4-6 weeks, removing tarp only if there is heavy rain. Check moisture periodically–if it’s dry the first inch, that’s ok, but water if it’s dry below that. You should begin seeing mycelium before long–the white, fuzzy part of the fungus before it’s in its mushroom phase
11.) When baby mushroom begins to appear, remove tarp and water 1-2 times a day. Drape with a shade cloth for 4-5 days until mushrooms are fully formed. Put chicken wire or something around area to keep deer/rabbits/etc. away
At the time of this writing, we have not actually put this plan fully into action yet. It may well be that we make some tweaks along the way–I’ll keep you updated! But for the time being, I seem to have worked out all the kinks–or at least answered my own questions as to how we’ll actually set this thing up. Fingers crossed we have a typical NW spring ahead!
*Keep in mind, every mycoremediation project is going to be a bit different–there is no cookie cutter approach that’s going to work for every project. You have to find the right mushroom for the job, take into account the site (climate, growing conditions, etc.) and and be willing to do some experimenting and pioneering in this emerging field! Unfortunately, there is no handbook for dummies just yet…;)
Other helpful links:
Making an outdoor mushroom garden with woodchips (not mycoremediation): https://www.milkwood.net/2013/07/10/making-a-wood-chip-mushroom-garden/
Video on making an outdoor Elm Oyster garden with straw (not mycoremediation):
Other mycoremediation projects: http://fungiforthepeople.org/mushroom-info/myco-remediation/