Is Masters Mix the Best Mushroom Substrate?

Having been growing mushrooms for almost ten months now, I have been taking a step back to critically examine my whole process. I have gotten a decent hold over the fruiting process and optimized the air flow, humidity, lighting, etc. I noted in a previous post that the temperature was one factor that I did not have a good control over due to having no powerful HVAC unit.

In doing all of the above, I have gotten to about 100 - 120% BE with lions mane and maybe around 100% BE with oysters. As experienced growers will note, this is far from optimal, with oyster mushrooms having a BE as high as 150 - 175%. Gary from Fresh from the Farm Fungus notes that a five lb bag of oysters should be able to produce as much 2lbs for a first flush whereas I have been getting more like 1 - 1.3 lb flushes. This is not too shabby and much better than before, but still not anywhere close to this famed 2 lb flushes.

I had actually bought Gary's book, Growing Gourmet Mushrooms for Market, and implemented some of the tips he had suggested relating to air flow. That led me to send him an email noting that I had bought the book and asking for tips. He replied with the following:

"What genetics are you using?"

"What substrates?"

At first when, I read his email, I thought those were fairly obvious questions and did not think that I was lacking in either quality of genetics or substrate. "I'm using the famed MASTERS MIX FROM TR FROM EARTH ANGELS MUSHROOMS substrate mix, which is optimal for producing large high quality yields" I thought to myself and surely a company as large as North Spore has what it takes to produce optimal grain spawn. I had used their spawn with great success over the past 9 months. Colonization was always fast and vigorous and fruiting seemed adequate - I always suspected that suboptimal yields were reflective of my lack of experience.

However, upon further reflection, I realized that those two components were actually critically important. If, as I always explain to people, mushrooms are more similar to animals and people, and less similar to plants; then, just as humans' health depends on the quality of nutrients they eat, so does that of the mushrooms.

So companies that sell masters mix substrate are not going to like what I am writing, and I don't have scientific basis for these speculative thoughts. However, it seems to me like masters mix is akin to fast food for mushrooms. You give them a huge nitrogen buffet and seek for them to grow as fast as possible and as large as possible. Think of the cattle industry where you seek to convert grain into meat as efficiently as possible. This leads us to the idea that the masters mix substrate optimizes for quantity and not quality.

Per GPT, most soy hull comes from Midwestern processing plants where beans are from massive GMO farms almost always sprayed with glysophate (Roundup) and often dicamba. By the time hulls reach bags, they've been through eat, cracking, flaking, solvent extraction, and chemical desiccation. The residues of pesticides are likely to remain in the hulls and the "negative energy" is likely to carry over to the organisms which eat it (i.e. the mushrooms) which then carry over to the people who eat that.

Of course, the fact that a plant is GMO doesn't mean that it's toxic. Genetic modification just improves herbicide tolerance or yield, so that's not necessarily the "bad" factor. What I'm more concerned about are the trace residues of pesticides found in the soy hull, which may carryover some sort of negative effect to those who ultimately consume it.

When I pressed GPT on this, it seemed to indicate that many experienced growers did seem to believe that 80% sawdust + ~20% oat bran produced higher quality mushrooms. The reasoning is two-fold: (1) the higher percentage of hardwood sawdust produces slower, but denser and firmer fruiting bodies - anecdotally, I have found this to be the case as well, and (2) by virtue of organic oat bran being cleaner produce than soy hull, I would think this confers some benefit to the quality of the mushrooms.

Having typed this out, I did press GPT on the sourcing for why sawdust plus oat bran/wheat bran was better, and it actually pushed back against saying that "Masters mix" is universally recognized as one of the most productive, reliable, and easy-to-replicate..." blah blah blah whatever, so maybe it was being a yes-man then. But now, I can't get it out of my head that masters mix may be the reason why my oysters and lions mane have been kind of fluffy and can kind of see why using a higher percentage of hardwood and oat bran would be better quality, although obviously it reduces yields.

Therefore, going forward, I think I am going to switch to using predominantly hardwood and organic oat bran as the supplement and see how the quality of the mushrooms changes.

Separately, I also realized that now that I have gotten better at the sterilization process, I can just sterilize grain and inject it with liquid cultures to produce my own grain bags. This will allow me to experiment with various liquid cultures from stores other than North Spore and it could be the case that other strains from other cultivators end up working better for me. This would also allow me to produce mushrooms in smaller batches than I was formerly as one 6-lb bag of spawn from North Spore can colonize up to ~30 - 40 5-lb bags

So basically, I was doing everything wrong - I controlled all of the fruiting factors except for the TEMPERATURE, which is one of the most critical parameters. I was using masters mix, which is like FAST FOOD, for the mushrooms - please don't get mad at me Mushroom Media Online if this information spreads, I'm just engaging in speculative thinking. And I was only using G2 spawn from a single supplier without experimenting with other strains.

Unfortunately, I am out of money and will have to retreat and hone my mushroom growing skills before I come back for round two. Till next time... Ja ne!