Krista , just my 2¢ since I know you'd like to learn, here's what I do... if I see active root growth, temperatures above 65 degrees F., active growing 2" or taller sprouts and lots of light for at least 9 hours a day, then I would give the equivalent of half strength miracle grow solution to tubers in a pot. Fertilizing, to me is an art, not an exact science. I fertilize pots differently than plants growing in the ground. The type of soil and it's ability to hold nutrients determines how often you need to fertilize. It really helps to learn the color of healthy leaves, and that will vary by variety, age and season. I like to keep plants growing in the ground sufficiently fertilized so they are nicely green to support lots of new leaves and sprouts. Pot tubers, as I understand, are best keep growing slowly. You should try to not have pot tubers busting out lush new growth, unless you want to take lots of cuttings.
