In the bowl of a full size slow cooker, layer the peas, barley, ham, carrots, onion and celery- in that order, and do not stir or combine.
In a large mixing bowl, stir together the broth, water, and spicing until evenly combined. Slowly pour the mixture into the slow cooker, without disturbing the layers. Stick in the bay leaf.
Cover the slow cooker to seal and cook on high for 4-5 hours, or on low heat for 7-8, or until the peas are softened & creamy.
Remove the bay leaf, and stir the soup together until thick, creamy, and evenly combined. Salt & pepper, to taste.
Serve immediately with crusty bread or crackers, if desired.