When planting boxes were bolted to the walls just below windows, they were given the name "window boxes." Today window boxes aren't always used in combination with a window. Window boxes may be used to bring seasonal color to a deck, patio or porch rail. Because of the limitations imposed on a window box, the way in which you plant this container is key.
Mix potting soil with water-retaining crystals for your window box soil. This will help your plants thrive in between watering on hot decks and patios or in windy locations.
Choose lightweight plants that will not cause structural stress on deck rails or wall masonry.
Pick low-growing and trailing plants that will look attractive, yet not obstruct a view through a window or from an outside seating area. Some choices for window boxes include ornamental peppers and herbs and trailing flowers such as petunias and ivy vines.
Place the container in its final location before filling with potting soil.
Put pottery shards over drainage holes to prevent soil loss through watering.
Fill box with soil mix.
Pull layers of soil back and put plants into the pockets between the dirt.
Push soil back over the plant roots.
Check plants frequently and water as needed.