I think the use of concrete in the kitchen garden is something that should be considered more often. Concrete is not pretty but since the main purpose of the kitchen garden is to produce edibles the benefits of concrete as a building material should be kept in mind.
The guy who started this garden I have now, back in the 1950s, was certainly very fond of concrete. In my post about soil improvement I mentioned the large 3 x 3 m (10 x 10 ft) concrete bed I found, I’ve talked about the concrete compost tube too, that I think he built too.
I also found an old concrete roller, that was probably used as a lawn-roller, but left behind in an old shed in the back of the garden.
What’s interesting is the age of the concrete roller – it says “1957” on the side of it! Written with a finger in the wet concrete. Now imagine a normal raised bed, perhaps waist high, made from this stuff, lasting 50 years! No need to worry about what type of wood to use, or count your money to make sure you have enough to buy the lasting type.
Concrete can also be used for aisles, as the perfect weed stopper between beds. A more flexible solution would be to pour your own concrete slabs that can be moved around, to be able to modify size and shape of each bed.
Lynn Mentgen-Gillespie talks about using store-bought concrete blocks, namely cinder blocks, in her ebook Cinder Block Gardens.
Be prepared to do some heavy work if you choose to use concrete in your kitchen garden, but at the same time enjoy the benefits of custom made tools and structures, that will last a lifetime.