.... but I have several Square Foot garden spaces and I used cinder blocks instead of wood to create the raised beds. Just a border of cinder blocks with an inside dimension of 3' x 14' or so, I have different lengths.
I did this because I like the raised bed square foot gardening method and wood won't last but a few years unless it is treated, which is not a good idea to use around food crops (the chemicals used to treat wood are very toxic).
I fill the raised bed with a mixture of peat, vermiculite, compost and good topsoil.
We have had good luck growing in these beds. I use a drip-irrigation style system (not really drip but more like flooding the top of the bed) to water. Weeding it trivially easy, since the soil is quite "loose" pulling out weeds is easy.
Also, we have planted things in the cinder block holes and that works well except that if the plants get big they interfere with your access to the bed. Last year I planted a couple okra plants in the cinder block hole, one of them grew HUGE with a 2' trunk!
My blocks are just placed on the ground, no mortar needed. You do have to level each block perfectly and it is a bit of work to put one of these beds together correctly.
Good luck!