My favorite raised planter is the CedarCraft Self-Watering Elevated Cedar Planter (link to Amazon). The planter dimensions are 22″ width 30″ deep and 48″ length. What I like about this planter is that it has an adjustable drainage system to allow full control over watering needs of the plants.
There is a water reservoir inside that helps prevent root decay and over watering. Although we aren’t sure how often we’ve made use of the reservoir system, it’s nice to have. It’s quick to put together and nice to have all the plants at standing height to tend to. We mostly use this for our fresh herbs we most often cook with.