Find a wide, flat spot with full sunshine and good air movement. Measure out your planting space. Allow at least 5 square feet in the planter to give yourself plenty of room for planting; make each side 5 feet long to achieve this spacing. Smaller planters are easier to construct and fill. Rake the site to level it and remove rocks and weeds, and mark your borders with flour.
Dig 2-inch-deep by 2-inch-wide trenches around your borders to accommodate the bricks. Keep these trenches as uniform as possible for a straight brick row.
Place the bricks in the trench on their ends to produce a 6-inch-tall loose brick wall. Even the bricks if you prefer an even look, or leave bricks slightly uneven for a more natural, rustic look.
Dig into the top 4 inches of soil inside your garden to prepare it for planting. Remove rocks, weeds and old roots. Lay 4 inches of organic compost and garden loam on the soil and work it in to improve soil quality and nutrition. Repeat this process until the garden is full to within one-half inch of the top. Add 13-13-13 fertilizer to the top 4 inches of soil to improve starting nutrition.