Hm... well... you should be getting roots. Maybe emulation of another grower might be in order.
To the best of my knowledge GW is pretty expensive. I have no idea how effective it is, but I've done some of my own experiments with the various myco/microbial inoculants such as Dr. Earth, Roots Oregonism, Humboldt Down to Earth (worthless, gotta double check the name on that, it's that worthless),
Mykos (great product, spendy), and the OGBiowar.
The OGBiowar so far is the easiest to work with and produces the most consistent results, with the
Mykos/Roots Oregonism coming in a close second. Dr. Earth is readily available, even at the supermarket now, and while it's a complete fertilizer (read: filler?), it WORKS and it works well. So well that the first time I used it I mixed it into a batch of soil as directed, but I did it on a canvas painter's tarp. I left it for two weeks, went to turn it and the tarp bottom was GONE. Completely eaten by the microbes. I got in some
trouble, oh man!
Either way, as far as the microbes are concerned, if you're dumping chemical salt ferts on top of them and the concentrations are high enough, you're killing them. P especially is deadly to mycorrhizae at concentrations higher than 10%, IIRC.