Purchase supplies.

Drill holes in the bottom of the buckets (if desired). Filling the bottom of the bucket with drainage rocks would also work.

Spray the buckets with one coat of spray paint using a smooth, even motion. Don't forget the top, inside edge of the planter that may be visible after planting.

Allow the first coat to dry.

Apply a second coat of spray paint.

When dry, fill with soil and your favorite plants.