I have the leaves that are curling under,but towards the ends they look nice and flat. Could this be from too cool of temperature . Will foliage spraying with epson salt help? And if so how much epson salt to a gallon of water should I mix? PH is all ways around 5.4-6.2 with coco and coco canna nuts at about 600 ppm at about 6 weeks old. I have the water timer set to go on at every 4hours for 15 min. and then off when the lights go off for the last 6 hours of darkness.