You could put that fertilizer in a bucket of de-chlorinated water with some compost and aerate it for 24-36 hrs. You don't have to use a cup -- maybe 1-2 TBS fertilizer and 1/2 cup compost to 2 gallons of water. The idea is to incubate the good microbes in the compost with added food -- just like letting bread dough rise.
I would predict a lot of bubbling with the added ferts. So you *may* want to use a 5 gal bucket only half filled to allow for the foam.