The most important window-box tips cover these three components: 1) how to choose the right type of box; 2) selecting the right plants that will thrive in the window box, and 3) how you will keep the boxes watered. Follow these tips for success when you're planning and planting window boxes.
Key Window-Box Tips to Remember
a) Make sure you choose rot-resistant material for your boxes
b) Assure they are sturdy enough to hold the weight of the soil plus flowers plus water
c) ThereWhether you buy window boxes or build your own, make sure they are rot resistant, they'll stand up to the weight of soil, plants and water and that they have drainage holes.
The best wood window boxes are made of treated redwood or cedar. Don't rule out inexpensive plastic boxes only because you don't like their look. They can easily be hidden by trailing plants.
Fiberglass window boxes are expensive, but they are beautiful, and their long lifespan may make up for the initial cost outlay.
Hanging Window Boxes
Use brackets slightly longer than the window box itself in order to leave space between it and the house. Measure from its front to its back. This prevents water from getting trapped at the back of the box, potentially damaging the house's siding.
Follow the manufacturer's instructions for installing the brackets. Make sure that the top of the window box sits a few inches below the window (especially if your windows open outward.) This placement leaves more space for plants to mound without totally obscuring your view.
Care of Window Boxes
To cut down on the weight that the window box must bear, fill it halfway with packing peanuts or Styrofoam pieces before you add soil and plants. Most annuals need only 6 inches of soil.
Window boxes—like any container—dry out quickly. You may need to water them daily.
Don't count on rainfall to adequately water your plants, particularly if there are eaves or gutters above the window box.
To cut down on maintenance and keep things looking beautiful, choose drought-tolerant annuals that bloom over a long period and do not require deadheading. Include plants whose best feature is their foliage, such as coleus and sweet potato vine.
Meghan Shinn is Horticulture's editor.