If you have a relatively sterile sand soil, like you might have if you live in Phoenix, Las Vegas, or the Gulf Coast, then you might benefit from it. Otherwise, maybe not. I have seen pretty dramatic results from golf courses installed with and without but the golf courses were always desert courses.

Not much lives in my soil except weed seeds, though I am trying to correct that. My thought was an innoculation couldn't hurt, possibly increase the chances that something nice would grow, and give me a fighting chance to grow bluegrass versus fescue. It would also seem that anything that increases nutrient and water availability to the plant would be a good thing. I also suspect you are quite right that one would never know the difference until the grass was in a stressful situation - like draught.

My thought was an innoculation couldn't hurt

Agreed. Spores of it came in one product I bought, but I can't say I noticed a difference. Since I don't generally allow my lawn to go into drought or food stress, I can imagine I wouldn't see much.

I have half a faint memory of reading somewhere or another that the fungi don't form symbiotic relationships with the grass at high levels unless resources are short. I could be wrong on that.

If correct, it would mean that an unstressed, well-fed lawn wouldn't benefit greatly. However, since an unstressed, well-fed lawn doesn't need to benefit greatly from it, I don't see a problem.

And like you said, I don't see that it can hurt.

I have a book that illustrates an experiment involving tree (I believe) roots and mycorrhizal fungus introduced at the time of planting. The root development illustration was overwhelming compared to the subject without mycorrhizal introduction.

Keep in mind that plants like trees prefer fungally dominated soil (per they type of nitrogen they offer) vs the bacterially dominated soil that grass typically prefers. For this reason I mixed in a big cup full of soybean meal with the soil (as well as a little compost) I used to pack in some newly planted trees last year to hopefully spur good early fungal development around the roots.

Myco is available but its expensive in most cases. Pentitington has a new product that's kind of interesting called "Smart Seed with Myco Advantage". Innoculated seed.
Don't know anything about it but I kinda hope it does well.

It's my understanding that (VAM)fungi don't travel from the surface down into the root zone. Innoculation would be difficult in an already planted specimen. One would have to get to the roots in order to innoculate. So use it before you plant.

Pretty interesting reading, but slow for me. I have to google all the big words and spend time with the pictures. Seems to take you down the road of the whole bio-nutrient and plant growth regulator applications. Third party tests don't really show the gains in quality the manufacturers show in their comparison photos, but say there is no visual decline when N is reduced. Worthwhile? I don't know, but probably a lot cheaper to add another grain feeding instead. Maybe when I retire someday I'll have the wherewithal to do my own tests.

I'd assume a good core aeration and dragging materiel into the holes would be about the only way to get the myco into the lawn grass - or injection of some kind.

I'd assume a good core aeration and dragging materiel into the holes would be about the only way to get the myco into the lawn grass - or injection of some kind.

Sounds like it, which is more time than I would bother spending for just that purpose. If you were aerating anyway, that might be a different story.

Some guys that fertigate have some liquid Myco injector additive thing-ey but lots stop using it. There is another newer product from a company called ICT Organics that has Myco in a CT extract for foliar or drench apps.