Reducing or preventing artificial medium contamination - the lazy way ?

Hello,

Once again, I have a very simple question (I'm kind of being ironic here).

I've been reading a lot about plants and their properties against a number of disease, problems, bacteria and pathogenic fungi. And a while ago I was trying out different mushroom growing kits: lion's mane, oyster mushrooms, reishi...

One of the issue was contamination by mold; and I don't have the hardware to sterilize, even in a 'DIY' way, with pressure cooker and such. I used to have coffee ground substrate, which is easily contaminated by green mold (just leave it in the open for a while), and have tried recently using wood substrate (saw dust, wood chips), which don't seem to "spontaneously" get contaminated (although it's kept dry so that's probably why).

The most recent mushroom I tried to grow are Turky tails (trametes versicolor). Two bags are contaminated: one with some kind of green mold (but it's not too big spots) and the other has that and some kind of cottony contaminant too.

So I've had the idea of using either essential oils, powder, infusion... either directly on the contaminant, or in the growing medium. A step further would be using one of these plants directly as a substrate, but I don't yet have access to large quantity of substrate to try this out.

There is at least one issue I can see with this : if the plant I use are also active against the mushroom I want to grow on that medium. So far, Buhner's books (Herbal Antiviral for instance) have been very informative, but mainly with pathogens that target man (like how sida spp will affect specific bacteria that can cause diseases). Does anyone know of plants that should be avoided to grow mushrooms such as oyster mushrooms, reishi, turkey tail, lion's mane... basically most of the medicinal and edible mushrooms ? I'm currently reading through one of Stamet's books where he talks about possible contaminants and so far a few antibiotics were mentioned. I don't have the material nor the experience to identify the contaminant properly, but at least for the green mold I'm thinking about aspergillus, penicillium or trichoderma. I have no idea yet what are the others.

What plants should I avoid using for the purpose of preventing contaminant ? What plants would also hurt the mushrooms I want to grow ?

My understanding is that working with sterile media IS the lazy way. It has been tried and tested and works reliably in pretty much all circumstances.

The problem pretty much comes down to one of biology. You aren't dealing with just one contaminating organism, which might respond to some kind of intervention like antibiotics. You are dealing with the whole environmental range of organisms - literally thousands of different species of fungi, bacteria etc... that are clamouring to contaminate your lovely primed and a ready food source.  Anything that might possibly kill all the potential contaminants is likely going to also kill you fragile mushroom spawn.

If you can't maintain sterility your options are limited to growing mushrooms that don't depend on sterility. A few of us have had success growing wine caps outdoor on woodchips. They grow aggressively and can cope with competition.

Michael Cox wrote:The problem pretty much comes down to one of biology. You aren't dealing with just one contaminating organism, which might respond to some kind of intervention like antibiotics. You are dealing with the whole environmental range of organisms - literally thousands of different species of fungi, bacteria etc... that are clamouring to contaminate your lovely primed and a ready food source.  Anything that might possibly kill all the potential contaminants is likely going to also kill you fragile mushroom spawn.

Yes, trying to get rid of all the contaminant would basically mean to annihilate all life on the substrate. And some contaminant seems to be helpful for the mushroom that is grown, so in a way it would be like sterilizing soil, killing the beneficial and leaving all the space for the pathogens or others.

It's an open question. Right now, my two bags of trametes versicor seems to be infected with trichodermas. Or maybe it's penicilium. So I guess using herbal antibiotics on these spots shouldn't be too much of a problem ? But then from a statistical standpoint. I might not have the cleanest chicken, but I'd be very surprised if I find bacterias and fungis that normaly grow on poultry feces or something similar. So maybe I could just use herbal antibiotics against the most common molds I encounter, preemptively ? I create my substrate, trying to do it cleanly although without sterilization. Instead of adding water, I add water infused with the herbal antibiotics targeting those most common contaminant, obviously avoiding the essential oils, herbs, or whatever else was used that would inhibit the desired mushroom.

Perhaps I'm better buying the material to sterilize. The optimal solution would be growing mushroom on wood logs, not wood substrate in plastic bags. It seems easier, and use less pollutants.

You can boil straw or wood chips in a barrel over a fire outside. No excessive temps/pressure cooker required.

If that seems like a hassle (it does to me 😁) you can soak your substrate in water with lime dissolved in it. I don't remember proportions, so you'd have to look that up.

You can also soak in regular water for a week or so to kill off any wee beasties. You're supposed to have a bit of water movement so things don't get anaerobic.

I haven't done any of these. I decided I'd better stick with wine caps cause they're the only things that might survive my neglect...and it seems like they have!

The lime has been ordered. And yes, boiling in a barrel seems like a hassle.

I've found the dosages here:

https://learn.freshcap.com/growing/lime-pasteurization/

Apparently it's about 6 grams per gallon of water used.

I'm wondering however how I can get rid of the resulting water in a ecological way (AKA throw it in the garden without it being a poison). Should I add something acid to it to neutralize it ? Or will I just die in a huge explosion if I try ?

Ok, I have a couple ideas.
Try adding barley straw.  It is used in ponds and horse troughs to prevent algal growth.  I don’t know that it prevents mold, but I grow oysters in untreated barley straw and have never had a mold problem.

The other thing you can do is switch what you’re growing and how you’re growing them.  
I’m probably pushing this too much on this forum, but try oyster mushrooms on untreated barley straw in 5 gallon buckets. It’s the only method I use to grow oysters now.  You can’t beat the yield and short time it takes.

I think there’s a misconception here that you can successfully spot-treat the mold that you see. That’s like playing whack-a-mole. Treat one visible spot and the fungus you can’t see will just pop up again elsewhere. Successful mushroom growing is dependent on sterile medium and there’s no real way to shortcut that. Believe me, I’ve tried. Same goes for trying to find a substrate or pre-treatment that would kill pathogens but spare your mycelium.   I think you’re just in for frustration unless you invest in a pressure cooker or at least a large pot to pasteurize your growing medium.

And when you’re inoculating here’s the poor-mans sterile technique: make some sort of frame to sit on a table. About as big as your table top and around 18 inches tall. This can be as simple as some PVC pipes. Set all your heat treated growing medium inside, along with your inoculant, tools, and a can of Lysol disinfectant spray. Cover the whole frame with clear plastic (like painters dropcloth) and tuck it in. Then with clean, gloved hands, reach under the plastic and spray EVERYTHING with the Lysol. Wait a few minutes then you can begin to do your inoculation in the relatively clean “glove box” bubble. Not as good as a professional HEPA filtration setup, but a lot better than nothing.  

Buying or building a laminar flow hood is on my long term to-do list.   I’ll probably inoculate enough grow bags in the future to justify it.  I have 16 bags filled with masters mix right now, ready for water to be added and cooking.  I plan on doing eight lions mane bags and for my first time, eight poppino bags.  Only time for the poppino as I’ll switch to chestnut mushrooms after I get more spawn.

I’m trying an experiment this year.  I’m planning on starting six oyster buckets the first week of each month, in hopes that I can have oysters available all year.  

I already have the buckets, so my cost each month is $4 for straw and $19 for spawn.  I figure at grocery store prices, less than a pound a month will cover my cost.  Production has started on past buckets at six weeks, with 2-3 flushes per bucket.