Ah, the lovely U-shaped bed. I maybe sort of kind of pushily pushed my husband on building this before we were really ready. However, he is so detailed and great at going with my flow that he did an incredible job.
This U-shaped raised bed is on a slope, so we actually had to adjust quite a bit for that. Lots of time with the level, but so worth it.
We will be tearing this guy out as we redesign the garden, but before we do I want to share how we built it!
Building a u-shaped raised bed
The bed we have is 12 feet by 9 feet on the outer edges, and then 3 feet in on all sides, with a 6 foot center.
I’ve drawn it out for you below. It’s 18” deep in most areas, and if you’re building this on a flat surface, plan for that. On the two ends ours is actually 12” deep since we adjusted for the slop and excluded an entire board to make things level.
The boards we used are untreated redwood, cut to size but starting out as 2”x10”s. We also then have 2”x2” supports in each corner, 1”x1” along the inner edges, and some rebar on the outside to reinforce the longer sides. There is a prettier way to do this, like create bracings on the inside that run horizontally between the sides of each arm of the bed. We did this as an after-thought and it’s worked out just fine.
A raised bed of this size took 3 cubic yards of soil - that’s a lot. We bought in bulk. However, the quality of the soil was mediocre. Do big research on this, but if need be fill your beds halfway with cheap soil and amend the heck out of it with compost.
Happy raised bed building my friends! If you have any other U-shaped raised bed questions, let me know!