Help! Variegated Ginger dying...
By Kimld
United Kingdom 
Hello! I live in London and I bought a Variegated Ginger two weeks ago (with leaves green/white on top and pink/red on the bottom). It looked great when I bought the plant and the day after all the leaves were kind of hanging down when the day before they were all rising up to the ceiling. We watered the plant and it appeared that some leaves were coming back up after a few days. Two days ago we turned on the heater (around 20C now) and it looks like the leaves are hanging down once again. Some leaves also have stains appearing or kind of little waves around the leaf (shown on pictures). The soil is moist and we did not replant it after purchase. Please help, I want to save my baby!!
The first photo is how the plant looked before and the remaining ones are the 'after' pictures.
On plant
Variegated Ginger
1 Dec, 2017
Your plant is actually Stromanthe sanguinea 'triostar', a tender perennial plant that can only be a house or greenhouse plant in the UK. It might be suffering transition shock (from being bought, brought through cold air, and into warm air in the house) but it needs bright daylight, with little or no sun (specially in summer), high humidity and no draughts, whether those be cold or hot. If yours is near a heat source, move it... don't let it dry out too much, but be careful with watering - these can easily get root rot, so never leave it standing in water - empty out any tray or outer pot 30 minutes after watering. I had a friend who had one of these on an east facing double glazed windowsill, directly behind the kitchen sink, and it seemed to thrive, but it was a relatively humid and cool situation compared with the interior of the rooms, though not cold, and it would not have appreciated having the windows open! Your plant may not be liking the dry air created by having the heating on, so increasing humidity around it is a good idea - a pebble tray twice the width of the pot, half filled with water with the plant standing on top of the pebbles (but not in the water) will help with that.
Inspect the plant closely and thoroughly, all over, backs of leaves and stems included, right down to the base, just in case it's come in with something unwelcome such as an aphid or spider mite infestation - spider mites are tiny and leave tiny bits of webbing, and can be quite difficult to see without a magnifying glass. If you find anything, you may need to spray with a suitable insecticide. In regard to the leaves changing position, this plant is related to the so called prayer plants, which fold up their leaves when it gets dark , see the link below for information re that, and care instructions - you will need to copy and paste into your browser
https://www.houseplant411.com/houseplant/stromanthe-plant-how-to-grow-care
1 Dec, 2017