Measure the space where the planter box will go
Decide the planter box dimensions
Choose weather-resistant wood or another suitable material
Gather materials and tools
Cut the boards to size
Sand the cut edges
Assemble the side panels
Attach the side panels together to form the box
Add corner supports if needed
Drill drainage holes in the bottom
Install a bottom panel or slats
Line the inside with landscape fabric if desired
Seal or paint the exterior if desired
Let the finish dry completely
Fill the planter box with soil
Plant flowers, herbs, or vegetables
Place the planter box in the desired location
Check drainage and stability regularly