My daughter had a Styrofoam fish box that she wasn't using...I had just seen a program on Wisconsin Public Television on making trough gardens out of fish boxes...so needless to say, I asked if I could have it. The first thing that I did was to use a wire brush and kind of scrub the box and really beat it up. It took all the indentations off and made it look really rough. I used some masonry paint in a lightish shade of gray to paint it. I gave it three coats. Here are some directions that will be easier to follow:
The idea and basic method was first conceived by the Scottish Rock and Alpine Club.Since then, they and others have tweaked the process to suit specific needs.
1. Find an empty Styrofoam fish box at your local fish shop, meat market or supermarket.You could use one of those styro boxes that steaks come in too. It must be strong. Most ice chests are not made of the right stuff, and may not be as durable. I have no idea if this one is strong enough...or if it will hold up during the winter. It will be heavy and won't be able to be brought into the garage for the winter.
2. Texture the surface to make it look more like natural rock. Be creative! There is no wrong way here. Be sure to go inside the trough as far down as to be sure that soil will cover non-textured areas. Use a stiff metal brush, your favorite gouging tools, a dremel, etc. Wetting the surface prior to texturing will help reduce the Styrofoam beads from clinging everywhere. Make ¾ inch drainage holes in the bottom. A small hole drill works slick, or a doughnut hole cookie cutter.
3. Brush off all loose particles.
4. Paint the surface with masonry paint. Masonry paint is more durable. Make sure you get in all the cracks and crevices you created.It’s not necessary to paint the bottom. Using more than one color of paint will make the trough more realistic. Your first coat will be the lightest color. You can buy a different color masonry paint, or mix a small amount of crafter’s acrylic paint or concrete coloring with the original color to change the shade. Drying between coats is not necessary. In fact, blending the colors is much easier with a wet surface. After your first coat, if you want to thin the paint with water before applying, you can. Be creative here too! Use whatever kind of faux painting method you want: paint brush dabbing, sponging, rolling rags, gentle rubbing, etc. All are useful.
5. You could also make Styrofoam feet for your Styrofoam trough. But make sure they cover a large surface area under the trough, rather than just the corners.
I have to put the holes in the bottom, for drainage and then select the plants to put in it. I think that I am going to put sedums and other alpine or rock garden type plants. When I get it situated and planted...I will take another picture. I think that Irish moss and Moss roses would look pretty in this too. Anyway, it has been fun to do and I'm anxious to get it done and out in the yard.