Rinse the 15 bean mix thoroughly and check for any stones or debris. Soaking the beans overnight will help ensure they cook properly within the recommended time.
In a microwave-safe bowl, combine the chopped carrots, celery, onion, and minced garlic. Cover with a damp paper towel and microwave on high for 3-4 minutes until slightly softened. This will enhance their flavor in the final dish.
In the Slow Cooker: In a 6-8 quart slow cooker, add the rinsed and soaked beans, diced ham, softened vegetables, diced tomatoes (including the juice), all seasonings, and chicken broth.
Cover the slow cooker and cook on low for 8 hours or on high for 4 hours, until the beans are tender.
Once the soup is done cooking, remove the bay leaf. Taste the soup and adjust the salt and spices as needed for your preference.
Ladle the soup into bowls and savor! This hearty bean soup goes perfectly with some crusty bread for dipping.