I'm using coco-coir as a medium. Fox Farms grow big liquid fertilizer. I have it mixed at half their recommended rate. Plants are about 12 inches tall. Is there a guide as to how much of the fertilizer to give at feeding and how often? I'm looking for an amount in ounces, if possible? I have already killed a plant and have cut waaay back on feeding. I don't really have any guidelines to go by and am just guessing.