Lay a 6-inch diameter PVC pipe on its side. Measure 4 feet from one end of the pipe with a tape measure and mark the spot with a marker. Saw a 4-foot section from the pipe using a hacksaw. Rinsing the pipe with water removes the plastic granules from the sawing.
Place the PVC on the ground so that it is vertical. Place it anywhere with adequate sunlight, such as inside your garden or flowerbed. Hammer the end of the PVC pipe into the ground. It should be in just deep enough that it is stable and stands on its own.
Pound two wooden stakes into the ground against PVC pipe’s side, one on each side. Wrap duct tape around the PVC pipe and wooden stakes. The stakes will help stabilize the pipe against wind and animals.
Pour sand into the pipe filling its entire length.
Core a 2-inch hole in the center of the sand-filled pipe using a broom handle. Fill the hole with potting soil, peat moss or compost. Sprinkle a few carrot seeds on the soil. Covering them with a sprinkle of soil protects them from insects.
Pour water in the top of the pipe. Continue watering the carrot regularly from the top of the pipe for 60 days. Once the seeds sprout, pull all but the strongest-looking sprout. After 60 days pass, start pouring generous amounts of water on the ground at the pipe’s base instead of in the top. This forces the carrot to grow longer as it seeks water.
Flood the pipe with water when you want to harvest the carrot, forcing as much of the sand out as possible. This reduces the chances of damaging the carrot when you pull it out. Grasp the carrot firmly with two hands and slowly pull it from the pipe.