flynfish welcome to the wonderful world of coco you should start feeding from day 1 I use canna A+B I mix up a ltr at a time my feeds are 1 ml liquid silica,4 ml rhizotonic,and 1 ml Canna A+B(each) ph'd to 5.8 at first each plant gets 250 ml of water just around the plant stem as you want your tap root to burrow to the bottom of your pot when the coco looks dry on top water again I feed every time with coco I started 2 girls they are 11 days old now and just upped there feed to 1.5 ml A+B per ltr of water hope that helps