Last year, I didn't bring my ginger in until after temps fell into the 40's and the ginger foliage all died down and the roots refused to come back to life until after new years -- a little sign of life around Christmas time but no real growth for another month or so -- I think I mentioned before.
This year, I brought it in before dormancy kicked in so the leaves are still green and the plant is continuing to grow.
But I just take a sharp paring knife and cut into the soil to take off as much root as I need. If I happened to get too much -- you really don't need a whole lot in a recipe -- then I wrap the washed root with plastic wrap and keep in the fridge. I used to put them in the veg bin, but I found it to be overly humid and/or the little piece would get lost and mold. So I keep my bit of ginger where I can spot it easily.
Squirrels are curious and dig in newly planted containers to see if someone might have buried something edible in there. If it found the ginger root and bit into it, it must've gotten a big surprise!