Overwintering ginger, a report from zone 7
I took the excellent advice from this forum last year and thought I should report the results.
I cut back all the ginger to the ground after the first frost, left some of the ginger in the ground and covered it with lots of straw.
The rest I dug up and brought into a chilly, but sunny room. I had two big ceramic pots (from the neighbor's trash, can you believe?) which I filled halfway with large stones and pure charcoal, then plopped a big chunk of the ginger (including attached dirt) on top of that & filled the pot with water, up to the base of the plant.
In early spring, the ginger in pots began to put out new shoots. By late spring, I uncovered the ginger that was left in the ground. Around that time I moved the pots outside to sunny spots.
I never got around to replanting the ginger in the pots. Occasionally I would add some weak plant food, but mostly I just kept adding water. The two pots now have stalks with flower heads on them, although this is over a month later than usual. The plants I left in the ground do not show any signs of wanting to bloom.
Next time I'll dig everything, keep in pots as described above and then plant in the ground when the weather is warm. That should give me blooms earlier than this year.