Hi All !!!
I would NOT mix fertiliser with neem oil!!!!!!
Mix the neem oil as directed! Spray plants, make sure to get underside of leaves that's where they live.
I spray till liquid runs off leaves.
Young plants and new clones will not like it and will stress badly.
Spray TOP and BOTTOM of leaves.
I lower the lighting level until plants have dried, not sure if that is needed.
Good Luck !!