Last year I planted my tomatoes in a row at the end of my plot in the Bolton Community Garden since I had already built and filled 8 raised beds and planting season was well underway. The plan was to finish the implementation of raised beds this spring with the addition of two 4x6 raised beds. These beds were going to be used for tomatoes along the long side of the boxes, planted 1 per square and trained up a trellis.
I began looking at alternatives, buy versus build, cedar versus composite. I actually bought a couple of cedar raised beds from The Farmstead. They had a 4x6 box using 5/4 rough sawn white cedar lumber with mortise and tenon joints, 8 inches deep. These same beds are sold by other vendors, including White Flower Farm. The best price was from The Farmstead itself, $104.50 for a 4x6 including shipping. Unfortunately, the specification were a bit lacking. The quoted dimensions were for the total length of the side pieces, including the mortise and tenon. When you assemble the boxes, the interior dimensions are a bit more than 3x5 feet, or 15 squares, quite a bit less than the 24 squares I was planning on. I decided to keep the Farmstead beds and use them at home for strawberries and herbs. For the community garden, I decided to build my own beds.
The decision to build my own was based on the discovery that Lowes carried 1x8 cedar lumber (the Home Depot I checked only had 1x6 and I wanted a little more depth for the tomatoes, despite what Mel says). So the boxes were going to be constructed of 1x8 cedar (Lowes had 8 and 12 foot lengths, which was perfect). I also bought some 1x2 and 1x4 pieces to use as corner blocks and as braces for the bottoms. The beds are going to sit on blocks to keep them out of the standing water that we frequently get after a hard rain, so I would need a bottom. I planned to use hardware cloth rather than plywood for the bottoms, with landscape fabric to keep the mix in the boxes. Assembly in the garage was fairly easy, as shown below.