There are only corner braces in the one box. I decided after that box that they weren't needed. There is a 2x4 spanning the bottom of each box in the middle for support so the sides don't bow.
I get 3-6 inches of rain per month - in spurts. As you can see my "yard" is totally flat, so when we get any significant amount of rain my yard is a swamp (I've had up to 2 inches of standing water for days in some spots - before it soaks in). So my garden the first year got way too much water and some stuff drowned (even planted in hills).
So part of the reasoning for the raised beds was to get them out of the water (you can't tell from the pics but I actually mounded up some dirt to build the beds on so that the wood would be out of the water as much as possible).
I'm on a well so I water with well water by hand. I want to build some rain barrel irrigation but my house does not have gutters so I'll need them and that involves more cost so it is on the future improvements list.
The boards are 2" x 10" x 10' (some are 8').
I have plenty of sun. The family that built my house did not want to have to mow around trees so they didn't plant any. I wish they had. My house is nearly 20 years old and would have such pretty trees if they had. I've planted a few oaks but they will take years to be of any significant size.
I need to take some new pics because I've already done a lot of planting (but no mulch yet - maybe this weekend).
aee96