I started tubers indoors, green stalk is thick 5 inches tall but green leaves are curling under. I have watered.
This could be an indication of some kind of pest activity, aphids for example. Have you checked for pest activity, are the leaves sticky? If so you can spray with water.
This leaf curling can also occur from water stress (too much or too little) or a nutrient deficiency.
It could also be a virus, which can be more difficult to diagnose. Viruses cannot be controlled with insecticides.
Here is a link to a previous post that might also help.