A good recipe for slow cooker vegetable soup uses 6 cups of broth, or water with bullion cubes, a variety of vegetables and spices. It takes up to eight hours to cook this recipe in a slow cooker on low, or up to six on high.
Three ribs of celery, two carrots, two medium potatoes, one onion and two cans of tomatoes make up the bulk of the vegetables. All vegetables should be chopped into small, bite-sized pieces before being added to the slow cooker. Other vegetables that can be added include green beans, cabbage, turnips and mixed vegetables.
Spices to add include minced garlic, salt, pepper, oregano and thyme to taste. After all of the dry ingredients have been added to the slow cooker, the cook should pour the liquid over and cover. The cover needs to stay on for the duration of the cooking process. To get more flavor from the aromatic vegetables, such as celery, onion and garlic, the cooks should sauté them in oil before adding them to the cooker.
A pound of beef cut into pieces of a similar size to the larger vegetable pieces can also be added to increase the protein and fat content of the dish. This creates between 10 and 12 servings.