critique my plan for indoor year-round oyster mushroom cultivation

Looking for some guidance on setting up a small-scale ongoing oyster mushroom growing operation.  I already have an outdoor winecap stropharia bed that yields 2-3 flushes per year from spring to fall, but I'm looking for continuous year-round production.  2-3 pounds per week would be plenty for my family of 5 – no interest in scaling up to commercial volumes.  

I would like it to be relatively low-tech and low-input cost.  I'm not fixated on the absolute maximum production, rather on using a mix of free and cheap inputs that give me a high chance of success.  Many of the sterile culture techniques seem overly fussy to me: glove boxes, flow hood, sealed rooms with airlock doors, pressure cookers and autoclaves, boiling 50 gallon drums of water for hours on end.  Hoping I can do away with some of that while still minimizing losses due to contamination.  I'm also not excited about the single-use autoclavable plastic bags; hoping I can reuse containers between batches.

Here are the ingredients I have available, and the ones I'll need to buy:

Mushroom mycelium culture:
start simple by buying bag of grain spawn online
eventually move to liquid cultures (malt extract solution) in mason jars with self-healing injection ports


Spawn run:

Quart canning jars – already have these for canning vegetables

Pressure cooker  - I'll need to buy one.    

Rye/millet - available for spawn jars $45/25 lb box = $1.80/lb

Wild bird seed: $11.99/35 lb = $0.34/lb



Bulk substrate run:

Spent grain from brewing beer  - ~15 pounds of malted barley that's been rinsed of most of its sugars.  Still contains ~5% protein plus all the cellulose

Hardwood fuel pellets: $5 for a 40-lb bag, less in bulk. $0.13/lb

Straw is expensive around here - $10-12 for a small square bale. $12.50/25 lb chopped straw @ TSC = $0.50/lb

Wood ashes – free.  Probably 20-30 gallons per winter

Hydrated lime: $20/50-lb bag



Here is my plan  - interested to hear any feedback, good or bad:

Start with rye-based grain spawn in quart jars, then inoculate @ 10% of bulk substrate weight prior to incubation.

My bulk substrate will be 80% hardwood fuel pellets, 20% spent malted barley, and maybe a pinch of gypsum.  Planning to try wood ash pasteurization, though info is hard to find online.  I have a pH meter to test the ash/water solution to make sure it gets above 11 pH.  I will soak my HWFP/spent grain mixture in this lye water overnight, then drain before packing into container and inoculating with spawn.

I plan to use plastic buckets for bulk substrate and fruiting blocks.  Probably 4-gallon kitty-litter buckets, nested together with one bucket intact and the inner bucket drilled with holes to allow oyster mushroom fruiting clusters.  I'm hoping the lye water mixture will be basic enough to pasteurize the buckets so they can be re-used several times.


Fruiting and harvesting:

I'll need to build something for this.  It may get hi-tech.  Growing indoors poses some environmental hazards – mushrooms want 95% relative humidity, and they drop a lot spores when they mature.  Both hazards for indoor air quality.  So the goal is to setup a mini environment for the fruiting mushrooms, but isolate it from the basement grow room.  My thought is to build a vertical two-chamber unit – maybe re-purpose an old refrigerator.  Divide into an upper and lower chamber with a solid shelf of some sort.  Fruit the mushrooms above, and use the bottom chamber to condense out the humidity and airborne spores.
Alternatively, I've also seen people start with a 4-tier mini-greenhouse shelf system and pipe in air from a humidifier.  As far as I can tell, this setup works well but the humidity and spores ultimately end up in your living space, which is not ideal.  The only low-tech setups I've seen indoors are a "misting tent" which is just a plastic bag over the fruiting block and a spray bottle.  I think this will be very hard to maintain the environment to get a good yield.

Eventually I'll need to learn how to build my olwn liquid cultures and take spore sprints so I don't need to continue buying cultures online.

But in the near term, I'm focused on reliably processing bulk substrate and getting the blocks to fruit

I've been growing oysters for several years now in the house and outdoors in 5 gal. pails. i have about a doz. 1/4in holes drilled in each bucket. i cover each hole with a piece of duct tape. i do 2 buckets at a time. i add 15c of hardwood pellets to each bucket. then add and mix in 3 3/4 c wheat bran or brown rice flour. i then boil and add 1 gal +2cups water and pour in to my hardwood pellets. cover and let set until the medium is just barely warm or you could let cool over night. next day with a disinfected glove/ arm, mix in about 2 cups of well broken up spawn. take a clean knife and put a slit in each tape covered hole. place in a warm place (70+) for colonization for 3 weeks. i open the lid and check it every other day but leave it to colinate for 1 week unopened. in about 3-4 weeks it should be all white on the surface. i then move it to a cooler dimly lit room and wait for pins to start coming out of the slits and push off the tapes. i then place the buckets in a clean clear plastic sterile tote with 6 2in. holes cut around the middle. stuffed with pillow stuffing. sterilize that too. mist with boiled and cooled water on all surfaces on the inside of the tote but not the mushrooms or the lid where it could drip on the mushrooms. wait for your shrooms to grow. you can usually get 3 flushes out of them by adding a cup of boiled/ cooled water to each bucket, after each flush. cover the holes with new tape with slits and put it back in a warm room again for 2 weeks to rehydrate. then repeat. when they arent giving many mushrooms anymore, you can use the spent spawn several times to inoculate  a fresh pellet mix. just use double the spent spawn than you would new spawn. I've added some spent coffee ground instead of wheat bran and it still worked pretty good. i use the warm weather oyster strain otherwise you would need a lot colder temps to trigger fruiting . it doesn't get easier than that. good luck!

Maybe it was just beginner's luck, but I followed the procedure here for bucket growing:  

Instead of 1/4" holes, I used 5/8" because that's the only bit I could find. Instead of aspen wood chips, I used cardboard from brown Amazon shipping boxes soaked in some dilute hydrogen peroxide/water (I followed instructions from another thread here on permies). I used the PoHu oyster sawdust spawn from Field and Forest. After one week, as the video said, I was seeing white filling in the holes of the bucket, which I did not open. At four weeks, I've got pinning through numerous holes and rapid growth. It looks like the bucket is absolutely stuffed because it's pushing out a little all over and seems "tight." Those clusters smell divine. I'm very excited!

I know cardboard doesn't have a lot of nutrition, but I have plenty of it and, if this is successful, will look into ways to boost the nutritional content. The reason I chose PoHu oysters is because they are supposed to be better for growing on all kinds of substrates.

Not really knowing what I was doing, I didn't put duct tape over any holes or do misting tent or anything else. I just today spritzed the pinning clusters a little with water because I'm not going to put them outside. I just want to see how they do indoors. They are growing aggressively, almost right before my eyes. No sign of anything iffy growing. If I can get a batch this way and am able to use the contents to innoculate another bucket or two for growing indoors, I'm going to be very happy. Five-gallon buckets stack so well. I use the Firehouse Subs pickle buckets at $2 donation each to help the firefighters; they are very good buckets, with removable lids and seals, very strong. I use them for all kinds of things in the garden.

I've used cardboard, toilet paper rolls, even old cotton t-shirts and jeans. as long as they are somewhat sterilized, the mycelium will grow on it. our air this time of years very dry so i need to make a growing chamber or they dry out quickly. in summer i just place them in a cool shady spot outside and they grow. the oyster i grow is a summer blue oyster that fruits at higher temps and is aggressive enough to out compete contaminants. i got it from northspore.com here in Maine. like i said, i mix in different things but hardwood pellets produce a lot of shrooms, are cheap and are already sterile from the pelletizing process. the boiling water kills anything else that might be in there. the recipe i gave above has produced the best for me.

steve bossie wrote:I've been growing oysters for several years now in the house and outdoors in 5 gal. pails. i have about a doz. 1/4in holes drilled in each bucket. i cover each hole with a piece of duct tape. i do 2 buckets at a time. i add 15c of hardwood pellets to each bucket. then add and mix in 3 3/4 c wheat bran or brown rice flour. i then boil and add 1 gal +2cups water and pour in to my hardwood pellets. cover and let set until the medium is just barely warm or you could let cool over night. next day with a disinfected glove/ arm, mix in about 2 cups of well broken up spawn. take a clean knife and put a slit in each tape covered hole. place in a warm place (70+) for colonization for 3 weeks. i open the lid and check it every other day but leave it to colinate for 1 week unopened. in about 3-4 weeks it should be all white on the surface. i then move it to a cooler dimly lit room and wait for pins to start coming out of the slits and push off the tapes. i then place the buckets in a clean clear plastic sterile tote with 6 2in. holes cut around the middle. stuffed with pillow stuffing. sterilize that too. mist with boiled and cooled water on all surfaces on the inside of the tote but not the mushrooms or the lid where it could drip on the mushrooms. wait for your shrooms to grow. you can usually get 3 flushes out of them by adding a cup of boiled/ cooled water to each bucket, after each flush. cover the holes with new tape with slits and put it back in a warm room again for 2 weeks to rehydrate. then repeat. when they arent giving many mushrooms anymore, you can use the spent spawn several times to inoculate  a fresh pellet mix. just use double the spent spawn than you would new spawn. I've added some spent coffee ground instead of wheat bran and it still worked pretty good. i use the warm weather oyster strain otherwise you would need a lot colder temps to trigger fruiting . it doesn't get easier than that. good luck!

simple and effective - I like it!

I got my winecap spawn from North Spore - very good quality and my outdoor woodchip bed flushes twice a year without hardly any work on my part.

Is your hole-y fruiting chamber getting enough fresh air to the mushrooms - no stunted or deformed small pins?  Do you open the lid to fan it a few times a day?  Any problems with breathing spores indoors?  I've heard some horror stories but I think those were people with dozens of straw bags fruiting indoors in a small commercial operation, not just a block or two.

I like the idea of using the old spawn to inoculate a new block, without going back to agar or spore syringes.  How long have you kept this going?  Do you eventually have to go back to buy new grain spawn from North Spore after # batches?

Are you accomplishing all this without a pressure cooker, or any sterile transfer techniques?

Davis Tyler wrote:

steve bossie wrote:I've been growing oysters for several years now in the house and outdoors in 5 gal. pails. i have about a doz. 1/4in holes drilled in each bucket. i cover each hole with a piece of duct tape. i do 2 buckets at a time. i add 15c of hardwood pellets to each bucket. then add and mix in 3 3/4 c wheat bran or brown rice flour. i then boil and add 1 gal +2cups water and pour in to my hardwood pellets. cover and let set until the medium is just barely warm or you could let cool over night. next day with a disinfected glove/ arm, mix in about 2 cups of well broken up spawn. take a clean knife and put a slit in each tape covered hole. place in a warm place (70+) for colonization for 3 weeks. i open the lid and check it every other day but leave it to colinate for 1 week unopened. in about 3-4 weeks it should be all white on the surface. i then move it to a cooler dimly lit room and wait for pins to start coming out of the slits and push off the tapes. i then place the buckets in a clean clear plastic sterile tote with 6 2in. holes cut around the middle. stuffed with pillow stuffing. sterilize that too. mist with boiled and cooled water on all surfaces on the inside of the tote but not the mushrooms or the lid where it could drip on the mushrooms. wait for your shrooms to grow. you can usually get 3 flushes out of them by adding a cup of boiled/ cooled water to each bucket, after each flush. cover the holes with new tape with slits and put it back in a warm room again for 2 weeks to rehydrate. then repeat. when they arent giving many mushrooms anymore, you can use the spent spawn several times to inoculate  a fresh pellet mix. just use double the spent spawn than you would new spawn. I've added some spent coffee ground instead of wheat bran and it still worked pretty good. i use the warm weather oyster strain otherwise you would need a lot colder temps to trigger fruiting . it doesn't get easier than that. good luck!

simple and effective - I like it!

I got my winecap spawn from North Spore - very good quality and my outdoor woodchip bed flushes twice a year without hardly any work on my part.

Is your hole-y fruiting chamber getting enough fresh air to the mushrooms - no stunted or deformed small pins?  Do you open the lid to fan it a few times a day?  Any problems with breathing spores indoors?  I've heard some horror stories but I think those were people with dozens of straw bags fruiting indoors in a small commercial operation, not just a block or two.
I like the idea of using the old spawn to inoculate a new block, without going back to agar or spore syringes.  How long have you kept this going?  Do you eventually have to go back to buy new grain spawn from North Spore after # batches?

Are you accomplishing all this without a pressure cooker, or any sterile transfer techniques?

i do open it daily. no issues with the spores. only boiled water added to the pellets is all thats needed. i can use the spent blocks 1x after the last poor fruiting before buying/ making more spawn.

Thought this video on a very commercial scale might inspire you.

Hi fellow Oystrians
Got a question pertaining the holes
once you harvested, does there even grow one back (the cut off) on the second or third flush?

Or do you need to push the mycelium back with a small plug of pasteurized medium? (I use cardboard)
Thanks!