Outdoor Planter Box - Free Plans PDF & Cut List

A 600×600mm planter box, 800mm tall, with a slatted finished look that hides a plastic insert pot. The slats let air circulate around the inner pot which prevents root rot and dramatically extends the box's life. Cedar is the right material here if you can find it — pressure-treated lumber is fine for the structural frame but should not contact soil directly.

Build the four sides as flat panels first, slat-by-slat, on a workbench — way easier than trying to fit slats one at a time onto a standing frame. Leave 6mm gaps between slats for airflow. The bottom isn't a sealed floor; it's two cross slats that support the inner pot from below, allowing drainage. Drop a standard 35-liter plastic planter pot inside and you're done.