Top: Minimal beds are a lot less function to build and fill, but demand double digging to prep soil beneath the bed. High beds imply considerably less digging and less stooping, but want additional soil and making supplies. Eleven inches is a common top: that’s two 2x6s stacked on edge. https://cedar-for-raised-garden-b28417.mappywiki.com/716931/raised_wood_garden_beds_things_to_know_before_you_buy