Place the planter pots parallel to each other and spaced 72 inches apart. Center one end of each 48-inch PVC pipe in each planter. Fill around the pipes with crushed granite or marble chips until you reach the top edge of the planter pots.
Apply PVC primer and cement to the top end of each 48-inch long pipe using the built-in applicator on the container. Apply primer and cement to the inside edges of the two elbows. Insert one elbow onto the top ends of the 48-inch long pipes. The primer and cement will form an instant bond.
Place the 72-inch pipe on a work surface and apply primer and cement onto each end. Insert the pipe between the 48-inch long pipes so that each end goes into the remaining openings on the elbows. Press the joints together to form an instant bond. You should now have a frame assembly.
Hold the shade cloth tarp over one side of the assembly with the help of another person. Slide zip ties through the grommet holes in the tarp and loop the ties around the pipes. Lock the zip ties and trim off the excess on the ends with utility shears.