Scrub potatoes and cut into 1 inch pieces. The smaller potatoes I just throw straight in.

Combine potatoes, garlic, and salt in slow cooker. Add water just until covered.

Cook on low for 4 to 6 hours until potatoes are nice and tender.

Drain potatoes and return to slow cooker.

Mash potatoes and add butter, buttermilk, and sour cream. Continue mashing adding buttermilk or sour cream as necessary to achieve desired consistency.

Season with salt and pepper to taste and sprinkle with green onions if desired.