The picture of the potted plants is a good example. Chances are that potting soil was sterilized and can benefit form an inoculation.

They were not sterilized. Both of those were fed with organic nutrients containing microbes and I used organic potting soil, which isn't sterile either.

​

Did you sterilize your yard before applying exogenous microbes? How can you attribute your results to this one application? ... The endogenous microbes that have existed in your yard are likely better suited for your environment than the handful of strains you get from a bug in a jug application.

I'm not the only one with good results: https://turf.umn.edu/news/arbuscular-mycorrhizal-fungi-amf-and-their-interactions-turfgrass-species

I'm willing to bet my yard did not have a blanket of hundreds of thousands of Glomus intraradices spores directly below my grass seed before I put them there. I have gardened with them and I have gardened without them, and I will never go without them again.

There's no leap of faith required - mycorrhizae have been known to enhance growth, fertilizer efficiency, and drought-tolerance for a long time.

I will say, your results are very good. That's a fantastic reno! I just wouldn't want to make the false attribution post hoc ergo propter hoc fallacy to say all of your hard work would have been a waste if you didn't spray outside microbes on your stand of turf.

Thank you, but I didn't work very hard. No aerating, no measuring seed, no measuring fertilizer, no soil tests, no fungicides, and aside from the first month, no watering. My results are consistent with what established science would predict, and I'm comfortable with that.