This design is inspired by a Burpee Seed Company design. The design offered here allows for use on any soil, and the need to dig a bed before setting this up is eliminated.
Vegetable beds, especially raised ones, need anywhere from 6-8 inches of loose soil for roots to grow, form and spread. Any raised bed made from standard 2-by-4 wood needs 3-4 inches of topsoil turned before the frame is placed down and filled with topsoil.
It does no good to set up a frame with narrow sides and lose crops because the roots can't penetrate clay, rocks, etc.
This raised bed is made instead from 2-by-8 pressure treated lumber. That allows 7.5" of height for root development.
Two ways of joining the corners are discussed. Securing the bed in place is relatively easy.
This project shouldn't cost more than $50, including the soil. That depends on the area and the type of soil used.
You will need:
• 2 each 2-by-8 pressure treated boards, 8 feet long
• 4-5 cubic yards of all-purpose potting or garden soil -follow this link to make your own
• 8- 2 foot long pieces of rebar
• 8 each ½" pipe clamps and screws
• Drill with bits and 3" wood screws
• Saw (if using method one)
• 4 each 4" corner braces and screws (for method two)
• Paint or stain if desired
• Level and shims
Corner method one:
Butt the edges together and use the corner braces inside the joints. This provides a very strong joint.
Corner method two:
Using the saw, cut a square dovetail as follows- on two of the boards, cut a 2" square out of each end of the corners. The piece of board left will jut out. On the ends of the other two boards, trace the cut out part on the first boards onto the other boards. Cut the middle part out, leaving the corresponding edges.
These two pieces will fit together like a jigsaw puzzle. Since they're square, they need to be secured. Pre-drill holes from the top of the board through the corner pieces into the middle on each corner, top and bottom. Insert one or two screws to hold the frame together.
For the bed box:
Cut each 2-by-8 in half and make a four-foot square frame. Set on a level piece of ground.
Measure and mark the middle of each board, and place the pipe clamps halfway between the mid-point and the corners, two inches below the top. Screw the clamps to the board, but do not tighten yet. The rebar will be driven through the clamps into the ground.
Using the level, make sure the sides are even. Use shims to raise any part of the frame that is below level. Carefully drive each piece of rebar into place, checking and re-adjusting level as necessary.
When completed, check to see how much above ground the box is. Spare treated wood, corrugated plastic or tin, landscape material, bricks or other materials may be used to keep the soil from washing out of the bed.
I use this rule of thumb- if part of the bed will be more than 2" above the soil to ensure level, I'll dig a trench for the other part to lower it so the wood contacts the ground all the way around.
Fill the frame
Using your favorite mix, fill the frame and plant your favorite fruits, vegetables or ornamentals. Water and fertilize as necessary.
Notes to consider:
• This frame is great for the square-foot gardening method.
• Use a third 2-by-8 and make a box 4 feet wide and eight feet long
• Mix and match different sized frames for a custom garden.
• Add frames and trellises for growing plants
• This method allows for other frames to be attached and the use of greenhouse plastic or shade fabrics
Enjoy your new garden spot. This works well even in the smallest of yards, and it is easily removed if necessary.