In a small bowl, combine the sour cream, buttermilk, the cider vinegar, and the dip mix. Whisk until the mixture is smooth.
Fold in the garlic and ¼ cup of green onion; set aside.
Core and cut the head of lettuce into 4 equal wedges. Place each wedge of lettuce onto four plates. Drizzle approximately ¼ of the salad dressing over each wedge.
Top each wedge with ¼ of the remaining green onions, ¼ of the diced tomato, and 1 teaspoon of bacon bits.