Beginner Gardening: My sweet potato vines keep dying! Help!, 0 by Mom2Josh

Mom2Josh wrote:
Hi there, I'm new to this website and this is my first post, I just registered this morning. I need help. Every year for the past 3 years since we moved into our home, I have planted sweet potato vines in my planters on the porch and they have grown BEAUTIFULLY, cascading down the sides of the planters and down across the porch. I'm very much a beginner gardener and these have always seemed quite simple to grow. But for some reason this year, they aren't growing. I've never had a problem with them before, but this year they're covered in brown dried up specks. Most of the leaf is green, but there are dried up crusty spots on them. I have been pinching the "dead" leaves off but they just grow back with the same thing. Little by little, my sweet potato vine is being reduced and I'm afraid in the end it'll just die. When new growth starts coming in, it's real shriveled and sick looking and almost immediately gets covered in the brown spots. When it first happened, I bought new ones and replaced the old ones but it just keeps happening. Do I have a bug? I honestly don't think I'm over-watering...any advice? There's a picture attached. It usually looks much worse than in this picture, but I had just pinched off the real bad ones. Thanks, Lisa