Fine-Tuning the Farm

Mushroom farming has been a continual exercise in patience and mistake spotting. In just the past few weeks, I realized that I had been making a series of mistakes - each large in and of themselves. I guess that it is not so easy just to quit your job and jump into another industry. While others have commended my bravery for starting this journey, I originally thought nothing of it thinking my choice to be mundane and easy - maybe others have a more realistic picture of what starting a new career path entails and I was overly optimistic...

A tell-tale sign that I am running out of gas is that I have been looking at accounting job postings and thinking of alternatives to explore should this not work out. I have had to snap myself out of this stupor and ground myself mushroom growing. I have yet 4 - 5 months of survival before I am completely out of money even without significantly increasing sales - and If I can increase them by a bit, this will stem the bleeding. Without further ado, here are the five major changes I made to the mushroom farm over the past weeks.

1) Changing the hydration rate from ~65% to 60%

While changing the hydration ratio from 65% to 60% doesn't seem like a whole lot, this is the water weight as a % of the total weight, so the math dictates nonlinear scaling. Assuming a ~2lb dry mass bag, 10% water weight result in a total weight of ~2.22 lbs (2lbs/0.9). 20% water weight would not result in ~2.44 lbs but 2.5 lbs. 50% water weight would be a 4 lb total. 60 % --> 5lb total and 65% 5.7 lbs. Therefore, although a ~5% difference in total water weight doesn't seem significant, it the difference between adding 0.7 lbs more or less of water.

I had somewhat suspected that I was adding slightly too much water to the bags. They seemed overly moist when inspected visually (although I still to this day do not really do "field tests" whereby the cultivator squeezes the wet substrate and confirms that it is hydrated correctly by feel - only a few drops of water should fall out when squeezed). Also, with my lions mane in particular, after sterilizing it, some of the substrate would stick to the sides of the bag after sealing and shaking the inoculum into it. This would allow the lions mane mycelium to crawl its way up the sides of the bags sniffing out the stuck sawdust particles.

However, I have never seen other cultivators struggle with these problems, and so I now realize that overhydrating my masters mix substrate resulted in overly wet substrate which clung to the walls of the bag more than it should have. I confirmed my suspicion with I read Michael Crowe's book which said use a 55% to 60% hydration ratio. Going down to 55% at 2lbs dry would result in ~4.44 lb bags vs 5.7% at 65% hydration. An over 1 lb difference! These small % changes in hydration matter a lot!

I am hoping that a more accurate hydration ratio will result in better colonization and fruitings and have been hydrating my recent batches accordingly. I have yet to see the actual impact it will make but suspect there will be a difference.

2) Intake air on top, exhaust on bottom

Originally, I had read online that I should place my air intake at the bottom of the tent and exhaust the air through the top on opposing corners of the rectangular/square grow tents. This would produce a natural flow of air across the tent minimizing dead spots. However, I also recalling reading that CO2 sinks and wondering why one wouldn't place the air intake on top and exhaust on bottom as this would align more with the CO2 sinking and then pulling it immediately out.

It may have been the AI just being a yes man because I eventually decided on intaking air through the bottom and exhausting it through the top. However, after reading Gary's book (from Fresh From the Farm Fungi), he confirmed that his set up is intake on top and exhaust on bottom for reasons of CO2 air flow. The CO2 naturally falls as is it denser than O2 and will travel downwards as it is pulled out by the exhaust fan. Of course, the oscillating fan inside the tent will still push everything around, but overall, it facilitates air flow as the sinking CO2 is naturally pulled out at the bottom.

3) Oscillating Fans

I currently have two 8x8 base tents and one 5x12 tent. I had originally bought oscillating fans to push air around inside of them but made the decision at some point to remove them, as I thought them a hassle to clean. This was a mistake - I noticed that my lions mane and oyster mushrooms' growth was much stimmier in their absence. I guess that the inline exhaust fans pull air out but do not contribute much to air mixing within the grow room and so dead pockets of air form.

I speculate that the CO2 would pool around the mushrooms due to lack of air flow and then produce stimmier mushrooms. Although now that I write this out, I thought that CO2 naturally sinks, so wouldn't it move away from the mushrooms as they breathe in oxygen anyway?

---- Chat GPT just says that it still makes a difference to have oscillating fans because mushrooms continually emit CO2 so it does pool around them without air flow.

Anyway, it seems more likely to me that they are more necessary now than not, so I have oscillating fans pushing around air at a low speed on a 15 min on/off cycle.

4) Placing humidifiers inside the tents

So, for this factor, I'm not a hundred % sure that it matters as much as they others, but I speculate that it may make a minute difference. I am using the same basement space for both colonization and fruiting.

Obviously, the colonizing bags emit high levels of CO2 as the mycelium breaks down the substrate and converts it into its living body. This raises the overall CO2 levels in the basement. It just occurred to me the other day that in order for the humidifiers to emit mist, there needs to be a fan pushing air through the nozzle. So if the humidifiers are placed outside of the tent, they are sucking in air in order to push the mist into the tent. Where is that air coming from? It is coming from the air surrounding the humidifier - in other words, the same area of air that is being filled with slightly higher levels of CO2 from the colonizing bags.

Given that we want to lower CO2 not increase levels of it, it doesn't make sense to spray higher CO2 air in conjunction with the mist over the mushrooms. I could be overthinking this, but given the level of mist necessary to keep humidity between 80 - 100% at different points in the mushroom lifecycle, maybe this is nontrivial.

5) Cleaning schedule

I had not had a vigorous and thorough cleaning schedule for my facility and am now in the process of cleaning much more thoroughly. A single vector like a bacteria infected humidifier can destroy yields.

I know have a rotating schedule whereby each tent rests for 4 - 7 days every ~3 - 4 weeks. This ensures that I am cleaning the grow room environment on a regular basis. I have also assembled a checklist of other possible vectors of contamination like the water tubing, intake air, intake filters, and more. Following these cleaning procedures will ensure that yields are not being suppressed due to the inadvertent cultivation of competitor organisms.

Conclusion

However, perhaps in making all these observations, I have missed the larger picture. One of the most important factors in mushroom farming is precise temperature control and unfortunately, I do not have that completely dialled in. Due to the nature of my basement facility, I have been keeping temperatures around 50 - 65 F, which is adequate but it is subject to the fluctuates of the weather. The basement being connected to overall home HVAC and poor tent insulation somewhat moderates temperature (in summer, home is cooler, so tents are cooler; in winter, home is warmer, so tents are warmer), but I am worried about mushrooms yields in coming months as the temperature drops further.

While, I have explored some "big" ideas like using the hot water line instead of cold water line to mist the mushrooms or even re-appropriating the home's hvac system to slightly increase the temperature in my facility, this still doesn't give me the precise HVAC control necessary for mushroom farming.

This kind of feels discouraging as I know that I am not able to precisely control perhaps the most important factor necessary for the cultivation of plants. A person can have access to as much fresh air or water that they want, but if they are exposed constantly to temperatures outside of say 60 - 75 - the normal comfortable range for people - they will be extremely uncomfortable.

This is to say that I should not be penny wise and pound foolish - I need to explore mechanisms for more precise temperature control in my basement facility or things will not end well no matter how well I tweak all these parameters. But alas, maybe that is the end of this endeavor.