Tapered Cedar Planter Box

Every side slat gets its long edges ripped at 5°. That slight angle is what gives the box its taper — the sides lean out as they rise.

Cut all the bevels in one session without touching the blade angle. Consistency is what makes the corners close.

Six long (24"), six short (14"). Three courses of slats per side.

Cedar is soft and splintery — score your cut line or use a fine blade if the top face is tearing out.

Stand a corner cleat vertically and screw the slats to it from the outside, one course at a time, leaving a small consistent gap between courses (or butt them tight — your call, gaps look lighter).

The cleats do the structural work. The corners are cosmetic.

Bring the four sides together around the cleats. Because of the 5° bevel, the corners should meet cleanly with the sides leaning outward.

Band-clamp or tape the corners while you drive screws. Bar clamps push mitered corners apart rather than together — don't fight it.

Screw two cleats across the inside, about 2" up from the bottom edge. Lay the bottom slats on them with 1/2" gaps between every slat.

That gap, plus the 2" air space below it, is the whole drainage strategy. Water leaves, air circulates, and the bottom of the box gets to dry out between waterings.

A solid bottom with four drilled holes will clog with soil and turn your planter into a bucket.

Screw the four feet on. The box should sit with an air gap under it — on a patio, this is the difference between ten years and three.

Staple landscape fabric to the inside. It keeps soil from washing out through the bottom gaps while letting water through.

Fill with potting mix (not garden soil — it compacts and drowns roots in a container). Leave the cedar unfinished and let it silver.