Soil, I'd like to grow some sweet potatoes myself, but I'm on the fence still about whether I'm going to grow my own slips or order some.
I'm thinking that since I've never done sweets before, I'd rather order slips because 1. I will know the variety I'm getting (just luck of the draw from the store) and 2. I will have one less thing to wonder about if they don't do well .
Variety is important because I don't have quite as long a growing season up here as they do down south so I think I would have more success with a variety that has a shorter time to maturity.