Questions about ginger

I've decided to try and plant some ginger root to create more. I read that I can use grocery store ginger, I just needed to soak it for a bit before planting. I did that and last year successfully grew several plants.... in one pot. This year I thinned them out into several pots. They are currently sitting in my fish room where I have a grow light (used for underwater plants, but has enough room beside the tank for terrestrial plants). They have not sprouted again yet. But I'm not worried. As I was researching, I noticed one source said that ginger plants typically just turn brown, die off, and go dormant in November. Mine did, and that's when I separated them into several pots.

1. I did notice that there seemed to be very little growth, maybe? I only got dime-sized rhizomes off of the old ones. Is that normal? I figured it might take a few years before I'm comfortable harvesting some to use in cooking and smoothies anyway. I'm just not sure what normal growth is.

2. I'm in zone 8a, but I'm trying to keep them confined to pots right now. We got hit by the winter storm and temperatures dropped to 12 degrees last month. That's the colest it has been in a long while. Temps normally drop into the 20's for a few days during winter, but it doesn't last. Would they actually be okay outdoors year-round?

3. Here in Georgia we also have tons of clay so putting them in the ground will be difficult. I put them in a potting soil (so there is perlite mixed in) and they seemed to have no problem sprouting, I'm just not too sure about the growth. The pots all have drain holes, so I'm not worried about that. Do I need to add a fertilizer to make them grow faster? Maybe just a specific nutrient? (With Aquatic plants, almost everything is broken down into specific nutrient sources because it's a tough balance between those plants and algae.)

4. I do some "hydroponics" as well. I know I can throw a sweet potato into one of my aquarium sumps or hang-on-back (power) filters, and add some light and they'll take off! I've also grown peppermint in a hang-on-back filter, and avocados as well. How well does ginger root take to "hydroponics"? Most of the plants I've dealt with that way were absolutely fine with the roots being constantly soaked, probably because the water was constantly circulating and "cycled" to keep ammonia and nitrites in check. The water wasn't just stale so it didn't promote fungus or excessive bacterial growth. Has anyone had success with ginger root growing like that?

5. After going dormant in the pots, how long does it usually take to sprout again? Should I have soaked them again before repotting? I was under the impression that the original soaking was to get rid of the growth inhibitor that the commercial farmers or distributors add once it is harvested. But does it do anything for the sprouting itself (other than allowing it to happen)?