Very good question since some gingers do grow naturally in more subtropical areas of the world where winter days my be dry and cool , with quite chilly nights and many of those do tend to die back for the winter with only the rhizome surviving to restart growth when temperatures warm once again and many of those , perhaps like the curcumas are started from bulbs or rhizomes with the store gingers perhaps being amongst that group , and i did grow one having started it indoors in late winter and then having planted it in a flower bed only to be frozen to death come our very cold winter , since I didn't bother to dig it in the fall for storage perhaps . I'm trying to recall if indeed the top didn't start to die back when the chilly fall weather set in , but it's been many years since I grew perhaps the regular cooking ginger so readily found in supermarkets -----Zingiber officinale

Right, that's why I'm wondering if maybe I left them out too long, and maybe the root itself is going to rot, or maybe this is perfectly normal.

I guess by the time I get an answer, it will be too late to do anything about it :(

Sorry to hijack your thread, criticalmass048, but I have almost the exact same question about my turmeric plant. I had this turmeric growing over the summer of this year, dug it up and brought it inside in a pot with standard vegetable potting soil some time around late October. It's looked great up until a few weeks ago. Now it's turning yellow and wilting. Haven't watered in a bit, but soil doesn't seem excessively dry. Just wondering if this normal behavior for indoor turmeric plants? I have a smaller one under a low power grow light that still looks lush and green. Thanks for any advice.

Just in case any one somehow finds this thread from a search engine or through houzz's search, the turmeric plants I was asking about in my previous post completely wilted away about a month later. The following April, I planted the root outside again and it sprouted sometime in June. I was able to separate multiple tubers from that one plant, which produce several more turmeric plants and a few tubers for me to use in cooking. I am overwintering several of those plants indoors again this winter, and I anticipate that I will produce many more plants this year, with this method and better/more intensive management of the plants while they grow.

But to answer my own original question (any for anyone else searching for an answer) -- yes, it's completely normal for turmeric to eventually wilt all of its leaves during the winter months, even if you bring it indoors under lights. Just continue to sparingly water it, wait for warmer temperatures and then plant it outside. It will regrow... at least for another year, haha.

edit - attached a picture of it growing outside, Aug. 18 2017

Here it is being overwintered in a south-facing window

here is another turmeric plant I was able to grow and overwinter inside from a tuber I separated from the original specimen.