Plastic Bottles instead of Pea Gravel Pea gravel and pebbles can weigh down window boxes. Empty water bottles are a lightweight option. Place rinsed bottles inside the planter and add soil on top of them. The space between the bottles will allow proper drainage without the extra weight.
Build a window box planter in 5 easy steps! Add curb appeal and improve your home exterior with a beautiful window box and some greenery and flowers. Step by step from construction2style on Remodelaholic.com