Well that is a heckuva lot of sulfur- are you sure 15%? A high level would be 1% or more!
If you INSIST on using it, it would be as a veg fert only, and to find the application level, look at other types of plant foods and find one with similar levels, and use that application rate.
But I sense that you will have trouble with that stuff. Really, fertilizer is something taht if you get the right stuff to start, it will save trouble down the road.
stinkyattic Reviewed by stinkyattic on . Fertilizer I have a 40 lbs fertilizer that is 18-10-5. I was wondering how much should I use? It doesn't say nothing on dosage on the bag. Rating: 5