I don't know it's one of those things I'm on the fence about and really wonder how much AM would be affected by a spring application of HyperCaP to kick start growing plants in colder temps...I'm not really sure what will happen...I guess I could try it on one plant and use I think its' Trypan blue to test for colonization...
Graeme Sait promotes getting things started with soluble P like that and innoculating. I did a similar thing last yr.
This yr I plan to rely on the micronized P...make the myco work at least a little bit.
No clue which is best though.
Edit...you gotta be sure they don't start too fast and get rootbound in the pot...but you know that