A wooden garden planter is an excellent way to define certain areas of your garden and to retain topsoil or potting soil for your plants. Since wood is naturally porous, it allows plants to breathe and will not inhibit their growth. Fortunately, you can build your own wooden garden planter yourself, even if you do not have much experience with carpentry. With the right preparation and materials, you can build a wooden garden planter in an afternoon.
Lay four 27 cm (10 1/2 inch) lengths of the 5 cm (2 inch) thick cedar board so that they form a square, with the end of each board overlapping the next board. Nail the square together, using two 5 cm (2 inch) nails at each corner. This square will serve as the base frame for the planter.
Lay two 30.5 cm (12 inch lengths) of the 2.5 cm (1 inch) thick cedar board on top of the base frame, aligning the edges of the boards with the edges of the frame. Nail the boards to the frame with 4 cm (1 1/2 inch) nails. These boards will be the base of the planter.
Drill six 1.25 cm (1/2 inch) drainage holes in the planter base, one in each corner and two in the centre.
Place one 30.5 cm (12 inch) cedar board upright against one side of the base frame so that the board is flush against one corner. Nail the board in place with 5 cm (2 inch) nails. Place a second board adjacent to this board to complete the first side of the planter, and nail it in place as well.
Nail six of the remaining 30.5 cm (12 inch) thicker cedar boards in place along the remaining sides of the planter.
Nail two of thinner 30.5 cm (12 inch) cedar boards to the opposite sides of the planter, using 4 cm (1 1/2 inch) nails. The boards should be on the outside of the planter, flush against the top edge.
Nail the 34 cm (13 1/2 inch) lengths of 2.5 x 5 cm (1 x 2 inch) cedar boards in place along the top edge of the planter on the remaining sides. Nail all the boards to each other at the corners with finishing nails.
Reinforce the corners of the planter by nailing a 2.5 x 2.5 x 25 cm (1 x 1 x 10 inch) board in place inside each corner. Use finishing nails to hold the corner braces in place.
Use pine instead of cedar if the latter is too expensive or hard to find.