Wood (gas) heated greenhouse

I worked in a commercial mushroom farm producing button mushrooms. The system they used was wheat straw beds about 8" deep laid in wood trays. The beds would be sterilized with steam heat, then inoculated with spawn cultured on grain from sterile tissue taken from inside selected mushrooms.

After the mycelia had properly colonized the beds, they were capped with about 2 cm of well made compost from hot compost piles, made from straw and horse stable manure.

The capping and a change in temperature then would stimulate a massive development of mushrooms, completely crowded from side to side. Successive waves of mushrooms appear until the bed material is exhausted. At times the beds would be watered with a solution of calcium chloride, I’m not sure if that was for the nutritional requirements of the mushrooms, or perhaps mold control or something else.

Oyster mushrooms can be grown in a similar way but on uncapped beds, or in plastic bags or tubes of shredded paper sawdust or straw with holes for the mushrooms to grow from.

It is probably a good practice to arrange for ventilation or filtration to deal with spores, as they can cause lung damage over time.


Ha, so the base mushroom food is in fact straw? Every sorce l read sayd they grow on compost beds with a thin line of topsoil.
Its realy easy if it works like you sayd!

I tryed it with mushrooms several times. Oysters on poplar logs, the snails and bugs ate the micelium before it culd sprout mushrooms. Wayted a year for nothing.
The rats foun the plastic bag with straw too, destroyed that too. I bought a button mushrom kit, that was a fail.
Never giveing up thugh :slight_smile:


I wasn’t involved in the bed preparation, but from what I observed the beds were simply damp sterilized straw.

They produced hundreds of tons per month that way, in cinder block rooms of 7 tiers of wooden frame beds, 3 stacks per room, about 150ft long. They were grown in complete darkness, button mushrooms apparently benefit from that, but oyster mushrooms required light stimulation of fluorescent lights.

Preparing mycelia culture requires biological laboratory techniques, flame sterilized tools, autoclaved culture media, and a laminar flow HEPA filtered booth in order to work reliably, otherwise it will just be mold and random fungus cultured. Or commercial spawn can be obtained easily, and could be multiplied by innoculating sterile media.

I have grown wild oyster mushrooms with some success by piling their preferred food here, balsam poplar, in shady spots in the forest. The trouble with outdoor mushrooms, especially oysters is that they are always infested with fly grubs that seem not slowed down by refrigeration. Rapid freezing or processing solves the problem, and the bugs taste just like mushrooms. :wink:

Oysters grown outdoors seem very picky, hard to predict. They are very specific to temperatures and seem to only emerge after soaking rains. They will emerge from the same logs for several years, so don’t give up hope on your project yet.

Shiitake can be grown similarly on oak logs innoculated with wooden plugs. The innoculant can be multiplied on fresh sawn oak sawdust.


Hi Garry
Do you have any pic and video from mashroom’s farm to explain more?

I don’t Saman, that was 30 years ago.

If I look around on the internet I should be able to find something similar.

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Apparently gypsum is added to the straw.

The metal bed frames are far better than the wood ones we used, but only necessary if stacking.


Not directly greenhouse related, but this is what my greenhouse produces every 3 days now.

My mic is bad so sorry for the sound. I wanted to show how great oak is as charcoal feedstock. The laminary grain structure produces dense, hard charcoal that allmost doesent dust when processed.
I weighed the bag later, it showed 14kg so that gives a bulk density of about 150g/l, unprocessed.


Update. Its s strange feeling walking from winter to summer bzt l like it!


This is what the inside of the kiln looks like while operating. This is when the kiln is starting to auto-heat.


And this is full blast. When the bottom lid is closed the pirolisis gas mixes better with air and produces a strong roar. The flame allso projects more verticaly heating the inner barrel more efficiantly.

Oh, and l shuld mention, l put in wood pellets for a test. There is 40 pounds of pellets in the barrel, shuld produce sbout 15 pounds of premium charcoal for my Mercedes :slight_smile:

I will later retort chunks and thin firewood as everyday char.


Hi Kristijant

I am curious! :thinking:

you do not notice any problems with plants because of the overheating of the roots?

What height of land is there above the flue? (height between ground surface and flue pipe)


Hi Thierry!

No, no plant roots overheating detected! The soil is in fact cold to the touch. There is about 60cm of sandstone above the flue, and soil is on the sandstone.
But, the flue doesent only heat up, it allso heats down and sideways. This means the flue heats about 10m3 of sandstone, wich is s lot of mass to heat, but allso s lot of mass to cool at hight.



So far so good. The winter is mild this year with temps around freezing all the time, so l only light the heater now and then. Still building the beds when l get the time. l stack lairs of mole hills, sand from the root celar, composted manure and chardust. Its up to worms to do their job of mixing now. And worms l hame MANY. So many, they atracted a mole in the greenhouse. The litle submarine now cruises in the bed, need to smoke the litle bugger out.


Very nice watering system you have. TomC


That has to be one tough mole after watching the sparks fly when you were digging the hole!


Envious is the word that comes to my mind.
Well, I do get to shovel, but only the white stuff (+ chunks of course).

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Impressive Kristijan! You must have put a lot of hours into hard digging. Also having the plants survive in -20 C shows you take good care of the mistress (stove) :smile:


Difference between heater on wood and heater on gas for me is that gas heater is way more stable and more secure, could be distantly operated and give bigger outcome in heating overall.

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Hi Jimmy,
Agree, but there is just one problem. Gas doesent grow free in my forest :wink: for next winter l will make a woodgas heater most likely, that will burn wood chunks/chips. Equiped with a thermostat to adjust the draft, shuld be a lot more automatisated thain it is now.