Here is a pictorial set of instructions for building a raised bed as taught by the Citizen Gardener class for about $25.
Materials (use regular lumber, not chemical treated)
- QTY 1: 2 x 10 – 8′
- QTY 1: 2 x 10 – 10′
- QTY 1: 2 x 2 – 8′
- QTY 32: 2-1/2″ deck screws (1 lb box is enough)
- Outdoor wood glue (waterproof)
- Cut the 2×10-8′ in half so you have 2 48″ pieces
- Cut the 2×10-10′ into 2 51″ pieces
- Cut out 4 9″ pieces out of the 2×2-8
Note: I cut the 48 inch pieces a little long because I actually cut the 2×10-8′ in half. The box doesn’t wind up being a perfect square, but no one notices!
- Joints are made using the combination of wood glue and deck screws.
- Attach the 2×2-9″ pieces to the long sides (51″ pieces) – locate the piece 1-1/2″ from the edge of the board (1-1/2″ is the width of the other board)
- Attach 48″ pieces (don’t forget to glue all mating surfaces)
- Ensure top edges of boards match so that top surface of bed will be level
- Check for squareness by comparing diagonal measurements
- Drill pilot holes to reduce the chances of splitting wood
NOTES: Drill pilot holes for the screws to prevent splitting the wood. Make sure no gap exists between two pieces of wood– the glue should be forced out of the joint if you have it tight. It is important for the two pieces of wood to be held together very tightly; this is the purpose of using screws. Your choice whether you install the screws from this side or the other side.
NOTE: You can see the points of the screws coming out of the side of the board, which will scratch a person walking by if they get too close. This is the reason we stopped using 3″ screws and started using 2-1/2″ screws. I like starting the screws on the 2×2 side instead of the 2×10 side because it hides the screw from view, the board splits less often, and I like have the head of the screw in the piece of wood that will rot first (will hold better for longer).
Done, you have a box that will hold 1/2 cu-yard of soil and is sized to give you 16 ‘squares’ of planting space!