hello
You can definitely use hydro nutes for soil growing. What I've noticed is hydro formulas are usually a little less strong... like a hydro bottle might read 3-2-4 and a soil bottle 5-4-6.
I would suggest doing as the label recommends and then evaluate if you need to do another application. I think we all forget sometimes that Less is More.
I found their website and it's showing 1ml/l for the first 3 weeks then stop.
https://advancedhydro.com/products/6/natural-root-stimulator