Are Green Potatoes Safe to Eat ?
Why Potatoes Turn Green
When potatoes are exposed to light their skins turn slightly green , this is caused by a toxic glycoalkaloid called solanine. Solanine develops if potatoes aren't fully covered by soil while growing, or if you leave them in the sun too long after the harvest, or aren't stored in complete darkness.
Because solanine is slightly toxic, it's possible to get sick if you consume a large enough helping of greened potatoes. Peeling or cutting away green sections before cooking usually eliminates the problem, as most of the solanine is located in the potatoes skin.