Using a 1 quart casserole, souffle dish, or any other high sided baking pan that will fit into your slow cooker, coat with nonstick cooking spray. Set aside.
In a large mixing bowl combine together 1 1/2 cups whole wheat flour, milk, 1/2 cup all purpose flour, honey, oil, yeast and salt. Beat at medium speed with an electric mixer for 2 minutes. Add the remaining whole wheat flour and up to 1/2 cup all purpose flour until dough is no longer sticky. If the electric mixer is have a difficult time mixing the dough use a wooden spoon to mix in the remaining flour. Transfer dough to the prepared baking dish.
Place dish in slow cooker and cook on HIGH for 3 hours or until the edges of the bread have browned. Carefully lift the baking dish out of the slow cooker using oven mitts or pot holders. Let bread stand for 5 minutes and than unmold on a wire rack to cool.