The good thing about using concrete blocks for your raised bed is that concrete will last for a lifetime. Although this one is being used for flowers you could just as well grow vegetables in it:
Photo by Liz (perspicacious.org).
Not to worry – take a look at these neat beds made from concrete slabs:
Photo by Jennifer Rafieyan.
The walls are thin but just as durable as wooden walls would be, and concrete can’t rot like wood can.
Normally the length of a raised bed would be longer than the width of the bed (oblong) but the one in the picture might work just as well. It’s important that you’re able to reach the middle of the bed without standing on the soil and thereby compressing it. The plants love a loose soil.
Another nice thing about the setup above is that you can use the same type of concrete slabs for walking aisles as you use for raised bed walls. Then you won’t need to worry about weeding your pathways, plus your shoes will be free of dirt when you go pick some fresh vegetables in the pouring rain.