There are many locations on the web that talk about creating a hypertufa trough, which is made from portland cement, peat moss and sand/pearlite/vermiculite. However, this is a very labor intensive and time-consuming process. Sharon Hartung and Evie Larson showed us a much simpler way to do it. The technique comes to us via the MN Chapter North American Rock Garden Society (www.nargs.org).
I found a similar set of instructions on www.twincities.com and have pasted them, below.
RECTANGULAR STYROFOAM TROUGH
Hunt up an empty Styrofoam fish box at your local fish shop or supermarket. Most are rectangular, about 14 by 22 by 7 inches. Clean the box, hose down with water and leave in the sun about 3 days until fish smell disappears.
Repair any surface damage with exterior wood glue. Fill side holes with Styrofoam cut from box top. Glue in place. Or cut out center of cover and glue rim to top of box to make it 1 inch taller.
Rough up outside of box and round off corners with a wire brush. Carefully cut or drill a few ¾-inch drainage holes in the bottom.
Brush off loose particles inside and out. Slightly melt surface Styrofoam granules with a hot-air gun, available at craft stores.
Paint surface of box with gray masonry paint. Paint the outside, top rim and top inch or two inside. To get a more realistic stone effect, add tan or black powdered concrete coloring to paint.
Cover drainage holes with small pieces of landscape fabric, nylon mesh or window screening. Fill trough with soil suitable for your plants, such as Alpine mix for rock-garden plants, cactus mix for succulents or regular potting mix for miniature hostas. Add a few carefully chosen ornamental rocks.
Plant the trough. Top-dress with gravel. Stand trough on a pair of bricks. Keep it well watered