How to Build Angled Planter Boxes With Wolmanized Wood

Measure a half-inch indent on the sides of each wooden slab. Rule a line between the half-inch mark and the top of the slab, along the 25-inch side, with the pencil.

Plane the sides of the wooden slabs down to the ruled pencil line, so that each slab now measures an inch smaller on one end than the other. Sand back any rough parts.

Arrange the slabs into a box, with all of the smaller ends at the bottom. Place the 18-inch slabs opposite one another on the inner side of the 20-inch slabs, so that around the top edge measures 20 inches on all sides. The planed sides will naturally make the box taper at the bottom to measure 19 inches all around.

Place a line of glue between each slab end and reassemble the box. Clamp the pieces together with the band clamp, then leave to dry.

Nail about 10 nails into each joint, on the 20-inch slab side, so that there are nails visible on two sides only.

Turn the box so that the smaller end is upward, then position the wood square over the top. The smaller end should measure 19 inches all around and meet the edges of the 19-inch square base. Nail the base onto the box.

Drill about four holes into the base for drainage. Turn the planter up the right way, now that the base is attached.

Sand the entire planter box. Wolmanized wood is naturally weather-resistant, so a varnish is not necessary---if you would like to varnish for aesthetic purposes, choose a natural oil- or resin-based varnish that won't be poisonous to your plants.