The green color may be the germ in the ginger body survived, in conversion ready to germinate, this kind of ginger can still be eaten. In addition, if the ginger is moldy and hairy or rotting, you should never remove only the rotten part and use the remaining part as food. Although the bad part doesn't seem to be very big, it's been saturated with toxins for at least a good portion of its life. To store ginger, pick a dry and ventilated place, and for more watery ginger you can choose to put it in the refrigerator or dry it out moderately.