By Norman Winter
MSU Horticulturist
Central Mississippi Research & Extension Center

Container gardening has exploded in popularity with about 47 percent of American households admitting to using some form of it.

There are a lot of great reasons to garden in containers, in addition to the fun. Compared to fighting tight, heavy clay in the landscape, it's also easier to provide a good environment when it comes to soil or planting mixes for your plants.

One form of container gardening starting to increase in popularity is the window-box planting. I recently visited a decorating store that was full of reproduction paintings. One painting obviously done in Europe in the 1800s really caught my eye. The narrow streets were lined with window-box plantings and created an almost festive look. It was clear that even way back then, people knew a lot about design using thrillers, fillers and spillers.

The reasons that people garden in containers vary, but almost half claim to garden for decoration. They want to enjoy the beauty of the flowers and have them enhance the home's outdoor appearance. So it makes sense that the window box is seeing a revival, too.

The rules for window boxes are similar to other types of container planting. Other than making sure you have holes in the bottom of your container or box for drainage, the most important consideration is a good, lightweight potting mix. It seems like wherever you look there are ads promoting the $1.49 special for a 40-pound bag of potting soil. As you pick it up, it even feels like you are getting 60 pounds for the same price.

Truthfully, this heavy product seldom yields happiness with container-grown plants. It is prone to holding water, which will inevitably prove fatal to your flowers.

Good lightweight potting soils are usually sold by the cubic foot rather than the pound. Though the bags are twice as large as the $1.49 special, they are easy to pick up and load. Many have controlled-released fertilizer mixed in. These bags are more expensive, but you will need fewer of them, and in the end you will have thriving plants.

Window boxes actually can be wooden boxes, brick and mortar boxes, or containers resting in iron frames. The end result, with flowers hanging over the rims, will be beautiful no matter what the boxes are made of.

You can stick with the recipe of “thriller, filler and spiller” for your window box, although I think the spiller takes on a slightly more important role.

The thriller plant (usually the tallest and planted in the middle) reaches out and grabs your interest with its texture or incredible beauty. In a window box, it can be a tall, colorful flower, or it can be a plant giving a grass-like texture, such as an African iris, a soft rush or an actual grass.

Spiller plants fall over the edge and can give a strong vertical element to the container if allowed to reach several feet. Here you might try a variegated vinca like Wojo's Gem, English ivy or even a sweet potato. You also can have blooming spillers like trailing verbena.

The filler plants may be greenery, colorful foliage or even flowers like Diamond Frost euphorbia, but they fill up the pockets in between the thriller and spiller plants.

Remember that as you water daily during the summer, your window boxes will quickly leach their nutrients, meaning you need to fertilize more often.

Container gardening -- whether it's in window boxes or large pots -- allows you to be the Monet of your project. Have fun.

Lori Hitchcock, owner of Natchez Trace Gardens in Kosciusko, will speak on this subject each Sunday afternoon at this year's Mississippi garden and patio shows.

The Gulf Coast Garden and Patio Show is Feb. 22-24 at the Mississippi Coast Coliseum in Biloxi. The Hattiesburg Garden and Patio Show is March 7-9 at the Lake Terrace Convention Center. The Jackson Garden and Patio Show is March 14-16 at the Mississippi Trade Mart on the state fairgrounds. For more information on these three shows, call the Mississippi Nursery and Landscape Association at (601) 919-8111.