Select sewer pipes that have not been treated with noxious chemicals, as these will leech into your plants through the roots. Don't use recycled concrete sewer pipes unless you know what they were used for beforehand and that they were not used with hazardous materials.
Cut the sewer pipe to size with a circular saw fitted with a masonry blade. Keep the blade wet per manufacturer's instructions using a trickle from a garden hose, if the blade requires it.
Roll the sections of cut concrete sewer pipe into place if possible and tilt them upright so the open ends are on the top and bottom. If not, use a dolly or a wheelbarrow and have someone balance the other end while you maneuver the pipe into place. For very large pieces, use a fork lift. Planters tall enough to sit on or lean against should be set 1 foot into the ground to help stabilize it. Keep this extra foot in mind when measuring the concrete sewer pipes for cutting.
Find out the average root depth of the plants you want to put in the concrete sewer pipe planter. If the planter is deeper, fill the extra depth will fill dirt, which is low-quality soil. Fill the rest of the planter with a mixture of compost and topsoil. The percentage of topsoil to compost will depend on the type of plants you use in the concrete sewer pipe planter.
Choose plants for the planter that will fit both visually and logistically. For example, a miniature fruit tree will not fit in a concrete sewer pipe planter that's only a foot wide. It wouldn't be stable, either. However, a miniature fruit tree would look and fit very well in a 4-foot-wide concrete sewer pipe planter, especially if it is surrounded by shallow-rooted ground-cover plants that spill over the sides. Plant your chosen plants and water them in thoroughly.