i use a fish emulsion solution that i soil feed and i will begin to foliar spray next week that the plants have more leaf surface area for absorption of the solution. I like to spray at the end of the day or at night when it is way cooler outside... I dont like to spray during the day because of the heat, it can cause marking and mold or mildew formation, not sure what Jorge Cervantes said, and if you do spray during the day, make sure to shake the plant as to not leave any large drops on the leaves.. Foliar feeding is a good mode of giving your plant vital nutrients it needs to grow... Im going to stop foliar feeding once i get 2 weeks into flowering, you dont or at least i dont want to spray the buds once they start forming, probably with water, but not the fish emulsion solution...
As for the amendments you are talking about, i have no experience with, so i hope someone who does helps you out, good growing bro