How To Make a Raised Bed Garden
A raised garden bed can have sides of any height. Six inches is plenty, but 1 to 2 feet is ideal, especially if you put in deep-rooted plants such as carrots. If you have a bad back or marauding bunnies, you might build higher. The taller the sides, the less bending -- and the fewer pests. Walls at 4 feet means pests are a thing of the past. Waist-high means you can perch on the walls while you work your garden. But that is a lot of soil to add!
Try combining different heights as pictured in this staggered design.
Keep the width 4 feet or less so you can reach the center without stepping in: You don't want to compact the soil. If you include a trellis or other structure along one side, keep the bed narrow enough that you can reach everything--2 to 3 feet.