How long will it take a potato to turn green when exposed to light?
It will depend upon the intensity of the light and duration of exposure. It also depends upon what you consider green (any slight hue or very green). Regardless, in our studies we saw green develop between 2 and 4 days, but this was under 23 hour light exposure.
Here are a few more Dr. Potato Blogs that cover this topic:
And, here is a communication from the U of I Extension on options for storing potatoes at home.