Make a mark 1 inch from the long and short sides at each corner of your board. Drill small holes with a ½-inch bit (four holes total). Continue to use clamps to steady the wood while you work. These will be the openings you thread the hanging rope through.
Editor's Tip: Make sure your planter holes are large enough to hold the pots, but not so large that the wood is no longer stable. If you're unsure, reinforce the underside of the shelf with thin metal braces,