Self-Watering Window Box

The best placement for your boxes are windows you frequently look out, as well as ones that are easily seen by passerbys. You may want to put them within easy reach of your garden hose unless you plan on watering them from the inside. If you place cork spacers behind the boxes, you will encourage air circulation and prevent a permanent damp area on your siding.

You can buy window boxes at any nursery or even make it a weekend project to construct your own. The best type is a natural wood like cedar or redwood with an inner liner you can remove in the winter. The box should be about eight inches deep and the width of your window. If it's a very wide window, break up the distance and make two or three boxes so none are too heavy or unmanageable. Make sure you use strong brackets to mount the boxes.

Another way is to make the window box a holder for several smaller containers. With this method you can rearrange you plants as well as replace any that aren't doing well.

Before planting your window box, cover the drainage holes with screen or another porous material so the planting medium won't wash out when you water. The best mixture for boxes is the commercial soiless mixes that are made of sphagnum peat moss, perlite and vermiculite. They are much lighter then potting soil, drain well, and retain moisture better.

When you are ready to plant, fill the box two-thirds full with premoistened soiless mix and then firm it down lightly. Lay your plants out on top. When you've found the look you want, sink them to the level they were growing in their original containers. The final level should be about 1/2 inch from the rim so you'll have some space to add water. This is one of the few times when planting more is better. The secret to full, lush, window boxes is to use lots of plants! If they outgrow your box you can always go back and take some out later.

After planting make sure you water well and then set the window boxes in a sheltered area for a few days--especially if yours are situated in the full sun. After you put them in their permanent location, water often (sometimes twice a day in mid-summer). Check them by sticking your finger in about an inch and testing for moisture. Don't wait till they wilt to water--but don't over water, either. Over watering starves roots for oxygen and also causes them to rot. Add a time-release fertilizer when you first plant and then use a water soluble fertilizer at 1/4 strength weekly.

The best planting design is to use taller flowers in the back, mounding plants in the middle and plants that spill over, in the front. You may want to tuck a few shorter plants in the back so you will be able to enjoy them from the inside. If you have shady window boxes you can still have beautiful plantings--even without impatiens. Partial shade is perfect for many of your houseplants such as pothos, hoya and philodendron, as well as outdoor annuals like caladium, coleus, lobelia, browallia and begonias.

When fall comes and the annuals in your window boxes are through, you can keep the show going by replacing them with chrysanthemums or other fall blooming plants. Even after the snow comes, you can still be festive by using your window boxes as holiday decorations with evergreen boughs and berries.  All you need is a little imagination (or a good book!) and you can have four seasons of outdoor decoration.

Read more on "Success with Pots and Planters" at Gardeners Supply.