1 Stab potatoes with fork. 2 Wrap each in foil. 3 Fill crock pot with potatoes. 4 Cover and cook on High 2 1/2- 4 hours. 5 Do not add water. 6 Cooking time depends on how big your potatoes are. 7 Use your best judgement. 8 It doesn't hurt to cook them for the 4 hours. 9 For large potatoes, I have cooked five to six on Low for 8 to 10 hours and they turn out perfectly.