Ginger doesn't store well - it will shrivel and dry up. I'd go ahead and plant it and keep it under lights or in the very sunniest window you can find. I have some edible ginger growing in front of the patio doors and its doing OK. I do feel that it needs more light, but it and the lemongrass I rooted are doing OK so far.

Mine is edible ginger. Maybe some of the ornamental gingers are different - it might help if you could identify the species.

Pot it up however you can for now. Mine winters in a 40degree garage.

Under lights.