Cedar Wood Raised Bed, 4 Posts, 4'w X 6'l X 2'h Northern white cedar wood is naturally rot resistant, essential for long-term use. We do not apply any chemical sealer or stain on the wood we use. We use 3/4" heavy cedar tongue and groove panels to construct the wall slats The tops of the 4x4 corner posts are chamfered, two sides are dado cut for the yellow cedar panels to slide in, the interlocking tongue and groove will lock the panels together providing a strong wall that will prevent warping The actual height of the retaining wall is 21" and overall height is 24" (w/post). Height of the cedar walls can be adjusted easily by adding or taking out cedar side panels.