Slow growing alpine plants do well in planting troughs made from stone or cement. You can use old polystyrene coolers or fish boxes as planting troughs to help reduce your environmental impact, and grow your decorative alpine plants. The key is to shape the boxes with a stick and wire brush to create the texture of stone and paint them with textured masonry paint in earth toned colours. A few holes in the bottom serve as drainage for the troughs. You will be able to reduce items going into the landfill and also add decorative troughs around your home.
Place a reclaimed polystyrene box on a work surface. Scrape the outside edges to create the look of a stone trough using a stick and wire brush. Sculpt the outsides of the box until you are satisfied with the overall appearance of the trough.
Move a heat gun over the sides of the box. Go just slow enough to see the sides glaze over and seal over where you scraped.
Paint the exterior of the box with exterior textured masonry paint using a paintbrush. Apply the paint thick and add more texture to the surface by striking over it with a trowel in a random manner until you are pleased with the appearance. Select two to three earth-toned colours such as grey, brown and black, and blend them over the surface to make a natural-stone looking trough.
Poke drainage holes in the bottom of the box with a stick every 6 inches along the centre and perimeter of the box. Lay a wire mesh panel over the bottom of the box.
Spread a thin, 1/2-inch layer of gravel over the bottom of the box to facilitate drainage. Mix organic soil, sand and small stones together to form the soil mix for the trough and fill the trough with the mix.
Set the trough on bricks or flat stones to allow for more effective drainage. Plant dwarf alpine plants in the trough and include small rocks as part of the display.
Wear eye protection. Operate the heat gun in a well-ventilated area.