In a large mixing bowl combine ground turkey, green onions, jalapeno peppers, garlic, Worcestershire sauce, salt and pepper. Form into 8 patties. Cover and chill patties for 1 hour.
Mix ranch dressing and sour cream together and chill.
Heat grill to medium. Place patties on rack. Flip two to three times for even cooking and browning. Cook 12 to 14 minutes total or until internal temperature reaches 165 degrees. Place 1 slice pepper jack cheese on top of each burger while still on the grill and let melt.
Split buns in half and place cut-side-down on grill rack over indirect heat. Grill until golden brown, about 2 minutes.
Place lettuce leaves and a burger on the bottom of each bun and top with 1 rounded tablespoon ranch sauce and top of each bun.