Put potatoes in the bottom of your slow cooker crock. Scatter flour over the potatoes; toss to coat.
Scatter bacon bits, red onion, garlic, chicken bouillon, ranch dressing mix, parsley, seasoned salt, and black pepper over the potatoes.
Pour water into the slow cooker.
Cook on Low 7 to 9 hours.
Pour half-and-half into the soup; cook another 15 minutes.
Garnish with Cheddar cheese and green onion to serve.