I got my sweet potato slips in and planted the first week of May. Due to traveling the past couple of weeks, today was the first chance I had to harvest. So they have been planted for approximately 120 days. My experiment using 15 gallon containers did fair so well. The production was pitiful. However, I have not given up hope. I plan to amend the soil to hopefully make it looser or is it more loose. And I will put up fencing as soon as next years crop is planted to keep the deer from removing all the leaves. I am afraid that might be part of my problem. I was not expecting our neighborhood deer to come in my back area by my raised bed garden. During the first week they removed almost every leaf on each of the potato slips. I put up fencing and that worked for the most part, but they did keep anything that grew up on the fence nibbled down.
New year I will be better prepared!!
Thanks Dave for the suggestion of Steele Plant Company. They were wonderful to work with and order from.