Planter boxes allow for better irrigation and drainage in clay or sandy soils by crating a raised bed, elevating the soil in the boxes above ground level. They also make it easier to garden by raising the level of the ground, which means you have less bending to do. Finally, planter boxes reduce weeds and other pest problems, as the plants are isolated inside the box making it harder for weeds to grow into them. Building a planter box offers a rewarding project that allow you to create a box that fits your exact needs.
Select the size of planter box you want to build. This will be determined by what you are going to plant in the box and where you are going to plant it. For example, a tomato plant wouldn't need anything more than a 2-by-2-foot box, where a cucumber or other vine-type plant will need a minimum 4-by-4-foot planter box.
Cut the lumber. The long sides should be cut to the exact length of the box. Cut the ends 1 1/2 inches shorter than the desired width.
Stand the wood on edge with the end pieces between the long sides. Start with a side and an end to make it easier to handle the boards.
Straddle the end board with your feet to keep it upright and use your hands to align the edge of the side flush with the outside of the end.
Predrill three pilot holes through the side board and into the end board. These holes should be smaller than the screw diameter. Most containers of screws will have this information somewhere on the box.
Switch from a drill bit to a Phillip's bit and screw in a 2-inch screw in each pilot hole. The pilot holes will prevent the end of the side board from splitting when you drive the screws in. Use either a stainless steel screw or a screw that is rated for exterior use.
Repeat the process for the other three corners.