Can anyone tell me why several leaves on my gingers turn yellow then crispy brown on the edges? I have several different varieties of gingers growing in pots. They all have the same problem. I have inspected the plants for mites, etc and have found none. I do not let the soil dry out.

I have midnight ginger planted in the ground. It barely grows and what few leaves it does put out does the same thing. The midnight ginger is planted in the shade.

I live between Houston and Galveston, Texas.