Place corned beef and 3 cups of water into a slow cooker. Cook on high until steaming, and then reduce heat to medium and cook for 2 1/2 hours. Remove the meat and add 6 potatoes and 6 carrots, each cut lengthwise, 1 small head of cabbage cut into wedges and 6 turnips cut into quarters. Place the meat on top of the vegetables, and cook on high until steaming. Reduce heat to medium, and cook for 45 minutes.
Place 1 cup of baby carrots and 4 cubed red potatoes into the slow cooker. Place turkey ham flat side down on top of the carrots and potatoes. Place 1/2 of a head of cabbage, cut into wedges, on top of the turkey ham. Add 6 cloves of garlic and 2 cups of chicken broth. Use enough chicken broth to cover the meat.
Cook on low for 8 hours. Add in 12 pearl onions, and cook for an additional 30 minutes or until the onions are tender.
A different recipe calls for adding 3 cups of chopped carrots, 4 cups of chopped potatoes, unpeeled, and 1 onion sliced into thin wedges to the slow cooker. Place the corned beef brisket into the slow cooker, and add enough water to cover it. Add the spice packet included with the corned beef. If desired, omit the spice packet and add 1/4 teaspoon of black pepper, 1 bay leaf and 6 whole cloves. Cover and cook on low for 10 to 12 hours. Remove the bay leaf before serving.