Add the cubed potatoes to the crockpot.
Add the diced onion, carrots, celery, and ham.
Sprinkle the salt and pepper over the ingredients.
Pour in the chicken broth and stir gently.
Cover and cook on Low for 6–8 hours or High for 3–4 hours, until the potatoes and vegetables are tender.
About 30 minutes before the soup is finished, whisk together the flour, heavy cream, and sour cream in a bowl until smooth.
Pour the creamy mixture into the crockpot and stir well.
Cover and continue cooking for the remaining 30 minutes.
Serve warm with shredded cheese, chopped chives, or your favorite soup toppings.