Living in Kentucky I wanted to make a planter that would use materials that are available locally, hence the bourbon barrel stave. Sawing and drilling release an aroma of oak and aged bourbon. Using the graceful curves of the stave I decided to make a simple yet elegant piece that stands on its own to showcase herbs and succulents.

Supplies

1 - 3 to 3 ½ inch wide barrel stave 34 long (This example is a used bourbon barrel stave)
4 - terra cotta pots 1 7/8 diameter base 2 7/8 top
3 - 1 3/8 course thread wood screws
Polyurethane

Tools:

2 1/8 Forsner bit (a hole saw can be used but it needs special treatment, see below)
1/8 Drill bit
Table Saw
Drill Press
Clamps
Tape Measure
Chalk line
Screw Gun
Paint Brush
Pencil

Step 1: The Build

This can be done with a single stave if you are careful.

A 40-degree angle on a table saw is needed for the upper piece. The top of this angle is 19 inches from the end of the stave. The remaining short end is then cut square taking as minimal wood as possible. This will leave you with a piece approximately 14 inches long.
You will then need to rip a small section, 2 inches off the rounded top surface to create a flat surface to connect to the longer piece. This could also be done by sanding it flat with a belt sander. Set this piece aside.
The longer piece is going to become your angled arm that holds the planters. You will need to mark a center line first to make sure your holes line up. Measure each end and mark the halfway point. Use the chalk line to make the center of the board. Measure 2 inches up from the end you previously cut. This is going to be the edge of the 1st hole you drill.

Step 2: Setting the Drill Press

This is the part that needs patience.

Set your drill press table to 40 degrees. You will need a piece of scrap under your workpiece as well. Align your workpiece so the 2-inch mark will be the lower edge of the drill bit and centered on the chalk line you made. Clamp the workpiece and the scrap piece to the drill press table securely.
Drill slowly and evenly, oak is very dense.
Take your time. (If you are using a hole saw rather than a forsner bit you will come to a point where the angled wood will contact the inside of the cup. You will need to remove the top of the wood with a saw to be able to continue.)
Once this hole is complete measure 2 inches from the edge of the finished hole and align the lower edge of the drill bit to this line and center. Clamp and repeat drilling for a total of 4 holes.

Step 3: Sanding and Finish

Using the shorter piece of wood, mark the centerline of the flat you cut and drill a hole 1 inch from the edge with the 1/8 drill bit. Half the distance between the center hole and the edge and drill a hole 1 inch in. Repeat on the other side. You need to make these pilot holes otherwise you can and will snap the screws.
Once you have these three holes, screw the screws in until only the tips are showing. Line up the two sections of wood to create a guide for drilling the second set of holes.
You can now sand any rough edges and burrs to make your project smooth. Paint every surface with 2 coats of polyurethane taking time to ensure it is fully dry before handling and re-applying. Follow the instructions of your particular polyurethane as some want you to lightly sand between coats.
Once fully dry connect the two pieces. This is enough to secure the boards as there is little weight from the plants to create stress.

Happy building.