If the box you are using doesn’t have drainage holes, drill some. Then line the bottom with gravel and add potting soil mixed with organic fertilizer. Choose plants in colors that pop against your home’s exterior, and then follow these steps.
1. Start with plants, not seeds, so you can play around with the design before committing to planting.
2. Rather than lining the plants up in a row, stagger their placement to create a lush display without any gaps.
3. Use a mix of flowers and foliage -- leaves act as filler and provide a neutral background for colorful blooms.
4. Place shorter plants and overhanging vines in the front of the box, where they won’t be blocked by taller foliage.
Martha Stewart Living, May 2014