Below ground crops according to the Farmers Almanac will be Oct 10 & 11.
That is when I will plant mine.
Mine were ready this year at the first of June. I took them out of the ground at that time and hung them in the barn to dry. The leaves started turning brown and progressed very quickly. Don't wait till they are all brown, take them when the brown starts.
During the winter months they were just starting to peek out of the soil and as the weather warmed they got maybe 3-4 inches taller before starting to really take off. Yes they did get nipped on the top if there was a heave frost, but it did not hurt the plants at all.
Watch them carefully in Georgia, you have been way hotter there than in Tennessee but I would think that you would follow the same directions. As soon as the blades start to turn brown dig one up and check it.
I plant mine in a huge farm tractor tire and they do great.
Hope this helps.
Nancy