Get to know everything about foliar feeding from this article, which includes why and how to use foliar sprays.
Another brilliant article from BigMike, which lets you discover when you should actually use 2 part nutrients for your hydroponic crop.
You certainly need a coco specific nutrient formula if you are growing in coco coir. So check out this incredible Advanced Nutrients products in this article.
Reading this article will help you understand how to balance your nutrient solution with 3 part nutrients and achieve bigger yields and full grow potential.