Peel potatoes and dice. In large saucepan, combine potatoes, diced celery, diced onion, water, bouillon cubes, and salt. Cover and cook until vegetables are tender, about 20 minutes.
*Do not overcook potatoes; they should be tender, not mushy.
Add 1 cup of milk to potato mixture and heat.
In mixing bowl, combine sour cream, flour, chives, and remaining 1 cup of milk. Beat until well blended. Gradually stir sour cream mixture into soup base. Cook over low heat, stirring constantly until thickened. Pour into bowls and add garnish.