Un-identified disease on tumeric plant

Hello,

Could some please help before all of my turmeric die? I am growing shade tolerant spices inside the house. Those that are doing fine are ginger and galangal, but the turmeric is having some challenges. They are all growing in the same kind of containers and soil, so I'm not sure what problem the turmeric is having when the others are doing fine. Please take a look. The young turmeric shoots are coming out yellow and dry. The edges of the mature leaves turns yellow, then brown, then dry up.

 

Soil seems mighty dry.
Looks like a lack-of-moisture issue to me.

 

I forgot to mention since I am growing it inside, I have sprinkled the top layer with sand to keep fungus gnats away. The bottom soil is actually moist but not soggy.