Combine a Whole World of Plant Life With Trough Gardening

"In the 1920s and 1930s people started tossing their troughs aside and replacing them with steel troughs," says trough-gardening expert Erin Scroll. "And gardeners gathered them up and started planting in them, and it became quite a rage." Nearly a century later, trough gardens are quite the rage once again. "I think they're gaining popularity because people are gardening in smaller spaces, and troughs allow a person to have a rock garden essentially on a patio."

Trough gardens can combine a whole world of plant life, including interesting rocks and microclimates to create a captivating miniature landscape. Plus, they're low maintenance, drought tolerant, and much lighter than the stone versions from centuries past. But one of the biggest benefits is that you can grow just about anything in a trough, including plants that are difficult to grow.

Troughs are fun and easy to make. All you need are:

Next, add the cement, and continue to mix with the rake. You can add cement coloring at this point if you so desire. (You'll find several different colors available at most home-improvement stores.) Once it's thoroughly mixed, start slowly adding water. This is where an extra pair of hands is really helpful because you want to mix and add water at the same time.

Scoop three or four shovels full of cement into the bottom of the box, and compact it nicely to form a sturdy one-inch base. Press hard on the base with your hands to get a nice, firm base; remember to wear safety gloves. The secret for forming the sides is to press down with your thumb and in with your fingers (figure I). Keep adding and firming the cement until it's the height you want. Don't forget to add drainage holes, you can either do it now while the cement is wet or drill the holes later. Cover the cement with plastic and set it in a cool, dry place. The slower it dries, the stronger it will be (figure J).

After about five days, rip the box away from the mold, and peel the bag away. For a more natural look, rough up the exterior of the box with a wire brush (figure K). Spray on a little water and rub on extra dry cement to cover any perlite that might be left exposed. When you're done, let the trough cure on the patio for at least a month.

Meanwhile, start collecting plants and rocks. Small alpine plants found in mountainous regions are popular choices for trough gardens because the lightweight concrete keeps the roots cool year-round (figure L). "It's a great way to grow alpines because you can manipulate the soil in your trough, whereas in the garden you're less likely able to do that," says Scroll. Alpines need porous, well-draining soil--such as a blend of sand, peat moss and humus.

Look for interesting rocks to add to your trough-garden landscape. After all, what's a rock garden without rocks to add height, dimension and character? Place a few petite plants (figure M) and cover the soil with small pea gravel (figure N).

If you want, cover the soil with top-dressing to help water drain away from plants. You may also want to prop your trough garden up off the ground for better air circulation (figure O).

Trough gardens get better with age. And another great thing about trough containers: they typically won't crack in extreme climates.