Oyster Towers – recycling your grow blocks
After a few mushroom harvests from your oyster mushroom grow kit or oyster mushroom sawdust spawn block, it can take on a new life
outdoors. You can mix the blocks with woody yard waste to grow more
tasty mushrooms!
You will need:
- fresh hardwood chips, clean straw or sawdust
- cardboard
- hog wire fencing
- grow kit or sawdust spawn block of king, phoenix, blue or pearl oyster
mushrooms
Find a location that is completely or mostly shaded – where no walls or
overhangs block precipitation. Start by placing a layer of cardboard
on the ground. This helps prevent native fungus from taking over your
towers. Affix hog wire fencing in a small circle, this can be
accomplished by bending the wire or zip ties (don’t use poultry mesh
because the smaller holes will hamper the natural growth of your
mushrooms). Add a layer of fresh wood chips, water well, then break
up grow block into golf ball size pieces and layer evenly on chips.
Repeat the process until spawn block is exhausted, spawn at a rate of
approximately 1:5 (spawn block weight: wood weight)- end with a layer
of wood chips. Water tower whenever it appears to be dry.
Branches used to make chips were collected over several months – in one day they were all taken for a free trip through the chipper shredder.
Towers were constructed immediately after chipping to reduce the risk
of native fungi and pathogens taking hold on the wood chips. For
pearl, blue and king oysters you will want to use hardwoods or fresh
clean straw. Phoenix oysters grow naturally on fir trees and can
survive on some other coniferous species, but you should stay away
from highly fragrant species that are known to be resistant to fungus
like cedar. A phoenix oyster tower can be comprised of some confer
chips but for best results, they should be mixed with straw or
hardwood chips.
These towers were started in mid-summer where temperatures exceeded 95°F for several days, even so, the first flush of mushrooms came after 40 days. Here in Tennessee and the North American interior the best time to start a mushroom tower is spring or early fall when there are mild
temperatures and plenty of rain. In the deep south or coastal regions
, oyster mushroom towers can be started almost any time of the year.
The mycelium will survive below freezing temperatures so it will make
it through the winter in most of the US as long as adequate water is
supplied.
Oysters, lions mane and maitake mushrooms grow naturally from the sides of stumps or dead trees. Building towers mimic the natural habitats and
fruiting behavior of these mushrooms. Shiitakes and pioppino
mushrooms can grow from the ground. For these mushrooms, towers aren’t
necessary. They will grow in a flat mushroom bed. Just like the
oysters you want to locate the bed in a shady area. Start with a
cardboard layer then mix spawn with woodchips or straw.
Oyster towers can be grown without any supplements to the wood or straw, however, studies have shown that small amounts of nitrogen or calcium can accelerate the growth of the mycelium, calcium sulfate (gypsum) 3% to
the woodchips or calcium carbonate 1-3% (lime) with the straw. Using
plant fertilizer for nitrogen is not recommended as it can burn the
mycelium, however, small amounts of manure, coffee or seeds can
accelerate growth. Don’t add too much- a little will go a long way.
As with most mushroom growing projects you need to be patient. These aren’t like plants where you see sprouts within a week, getting mushrooms
within a month would be a very exciting result.
The mushroom mycelium in the grow blocks enzymatically breaks down wood for food, in turn, it uses the energy to grow more mycelium and mushrooms. The mushroom towers are a good illustration of how all life breathes no matter how small or inconspicuous – as the mushroom mycellium grows and breaks down the lignocellulose in the tower it respires CO2 and water. You can see how quickly the towers dry out due to constant respiration of the hungry mycelium!
