Pound the pipe about 12 to 24 inches into the ground with the sledge hammer where you will plant the tomato seedling. Make sure the pipe is straight and sturdy.
Bend the ends of the 6-foot-side of the wire fencing with pliers, making hooks that fit around the pipe.
Stand the section of wire fencing next to the pipe with the hooks around the pipe. Tighten the hook ends of the fencing and twist them secure so that one edge of the fencing is attached to the pipe.
Form the wire fencing into a cylindrical shape with both sides meeting the pipe.
Use the zip ties to fasten the unattached side of the wire fencing to the pipe. Start at the top and secure the wire fencing to the pipe every couple of inches.
Plant the tomato seedling in the center of the wire fencing tower and water and mulch it well.
When the tomato seedling begins to grow up and branch out, gently fasten the largest branches to the wire fencing with soft material such as old nylon hosiery cut into strips.