MSSF Cultivation Blog

Mushroom Garden Beds Using Far West Fungi Farm Mushroom Sawdust Loaves

Posted on 03 November 2011 by klitchfield

If you joined us on the Far West Fungi Field Trip and brought back some of the mushroom sawdust blocks or loaves to use in your garden, here’s some info on how to treat them:

The loaves with the leathery chocolate colored skin are shiitakes. The rest that are white are most likely white, brown, or gray oysters. Trumpet oysters form white sheets of mycelium on the top of the block that often retain the thick cut bases of the trumpet oysters. The loaves of golden or pink oysters should have some remnants of those colors on them. In addition you may by chance have some of the less common Reishi, maitake/hen-of-the-woods, or lion’s mane/crabalone.

First cut any mushroom stems remaing on the loaves down to the surface of the sawdust so they don’t continue decaying.

Soak the loaves in water in a wheel barrow, tub, or barrel with a weighted board on top to keep them submerged for 12-24 hours (not longer at one time as they may drown). Some folks like to soak them in hydrogen peroxide water as it kills off the mold some, though this is an extra overhead step that isn’t necessary. This should be no more than .3% concentration. That would be two bottles of 3% H2O2 from the drug store poured into a 5 gallon bucket and fill with water. After 24 hrs the H2O2 decays to water and can be poured off into the garden.

Put the soaked loaves of sawdust bottom side down on a bed of chippy wood chips 6-12? deep and 3×3? or 4×4?, or longer in length if you have more blocks. You want chippy wood chips from logs and branches as they are the better food for these wood eating mushrooms than leafy or twiggy stuff that doesn’t last very long and gets more mold and bacteria. On top of the wood chips should be placed one or two layers of unwaxed carboard as the bottom of the blocks are more likely to leap off and grow into the chips if they are in contact with the layer of cellulose cardboard against the surface of the bottom of the loaf. The blocks should be placed side by side butted up against each other and they will often grow back together sideways, especially if they are all of one kind like shiitakes or oysters.

On top of the loaves of sawdust you should place fluffed up straw, excelsior, or draped burlap as a humidity layer for the mushrooms to sprout up into and not dry out. Excelsior is the stringy aspen wood fibers sometimes used in packaging material instead of syrofoam peanuts. If you use burlap you can place stakes in and around the bed to tent it above the mushrooms.

A simple way of taking care of the cardboard layer and the humidity layer is to place the loaves in unwaxed cardboard boxes on top of the wood chips. The blocks can be placed one layer deep in a cardboard box side by side in contact with each other filling the bottom surface of the box. The box should be the depth of the block height plus that much more to allow the mushrooms room to grow above the loaves. The flaps on the top of the box provide the humidity layer when the box is folded closed.

When the loaves are installed in your mushroom beds in a shady, non windy part of the garden the rains will keep the blocks and humidty layer wet all winter long during the November to May rainy season with very little work on your part, except to harvest mushrooms. If the weather goes through a dry spell you may have to water periodically.

Ideally the mushroom loaves will send out mycelial tentacles down into and through the cardboard to the wood chips anto pick up more nutrients to add to the blocks. If they don’t “leap off” they will at least continue producing mushrooms out of the sawdust remaining in the loaves until they are used up in a few months to a year.

Your success may vary depending upon how fresh the blocks are and the type of mushroom and how regular the rains are in the season as extra watering maybe needed. Check through the straw/excelsior/burlap once a week or so for fruiting mushrooms and keep the straw fluffed so it doesn’t get compacted.

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