Planters are ideal alternatives to in-ground gardens when soil quality is not ideal or for area where an in-ground garden is not an option, such as a terraced apartment or patio. Planters come in many different designs, using many different materials, but wooden planter boxes are among the most popular styles of planters, especially for larger designs. While commercially made planter boxes are available, you can save quite a lot of money by making your own.
Lay the two 36-inch-long planks on the ground, about 12 inches apart when measured from the outer edge of the planks. Lay the three 12-inch-long planks evenly spaced on top of the two 36-inch planks, with the ends of the 12-inch planks flush with the sides of the 36-inch planks.
Nail down the 12-inch planks, two nails into each 36-inch plank, 12 nails total. This is the base of the planter.
Arrange the wooden sheets into a box shape, so that the two 36-inch sheets form the sides of the box and the 12-inch sheets are the ends of the box. Place a line of wood glue at the meeting point of each wooden sheet, then place the band clamp around the box securely. Allow to dry.
Nail the corners of the box together, putting six nails, two inches apart, into every joint while the band clamp is still on. Remove the band clamp after nailing the box together.
Place the base of the planter, with the bottom (the side with the two 36-inch planks) facing upwards, over the top of the box. Make sure the edges of the base are flush with the edges of the box, then nail the base down---one nail every two inches around the entire perimeter of the box---48 nails total.
Turn the box, with secured base, right side up, so that the base in now on the bottom.
Sand the entire planter, then remove any dust with a dry paintbrush.
Varnish the box using a natural oil or resin derived varnish. Avoid using a polyurethane varnish, as it can deteriorate and leach chemicals into the soil with prolonged exposure to UV rays.
Line the planter with a plastic garden sheet to help protect the wood from premature rot. Poke a few holes in the bottom of the plastic before filling it with potting mix to facilitate drainage.