Let’s bump you to the top so someone can answer your question.

I’ve only used it around the roots and soil when transplanting. (Free samples)

I've never heard of overdosing microbes, so I don't think you need to worry about that. I use a half teaspoon of Great White per gallon of water, every other week. With a granular form, I'd go with a teaspoon per gallon of soil for starters, and inoculating the root ball for transplants. You might check the instructions with whatever product you're using.