Abstract: A tapered planter box includes a bottom surface extending in a plane and a plurality of sides extending upward from the bottom and defining an interior. Each of the plurality of sides tapers outward from the interior at a taper angle. Each of the plurality of sides includes a first plank extending along a longitudinal axis. The longitudinal axis extends generally parallel to the plane of the bottom surface. The first plank has a body and a tapered dovetail extending therefrom along the longitudinal axis. The tapered dovetail includes an outer trapezoidally shaped surface having a first size and an inner trapezoidally shaped surface having a second size, larger than the first size. The dovetail on the first plank on each side interconnects with the dovetail on the first plank on an adjacent side.