Raised planter boxes are structures that allow you to plant a garden in any area, which is advantageous when soil in your yard is poor. Planter boxes have the extra benefit of being raised from the ground, making weeding and planting easier on the back and knees. The shape of a planter box also allows you to walk all the way around the plants without stepping on the dirt, preventing soil compaction and treading on former sprouts.
Place your timber into a square in the final location of the planter bed and use your shovel to mark around the timber. This makes an outline for digging a trench.
Dig a 6-inch trench, making it as wide as the timber being used. Fill the trench with 2 inches of gravel and place your timber on top. Remove all grass from the center of the planter box area.
Place a piece of lumber diagonally across the timbers and place a level on top. Check to ensure all corners of the timbers are level, removing dirt until they sit even.
Drill a hole into the ends of each piece of timber, large enough for your pieces of rebar. Drive the rebar into the soil using a sledge hammer until the rebar is flush with the surface of the timber.
Layer new pieces of timber on top of the timber base, overlapping the corners so that all timber is facing in the opposite direction. Secure the timber using a timber screw. Continue layering the timber until you reach the desired height, securing each layer with a timber screw.
Drill holes into the side of the planter wall so water is free to drain from the soil. Place a small piece of copper pipe inside the hole to prevent wood decay.
Place pieces of lumber on top of the timber to create a railing area. Miter the edges of the lumber so that they fit together at an angle, and secure the edges together using wood glue. Screw the lumber into the timber below using decking screws.
Fill the planter with dirt and plants.