You need 2 liter bottles, potting soil, seeds, thick string or yarn (either cotton or poly seems to work), a Phillips screwdriver, hammer, and a sharp blade to cut the bottle. Cut the bottle in half. Use a Phillips screwdriver and a hammer to punch a hole in the center of the bottle cap. Cut a length of yarn/string about 1′-1.5′ long, double it over and tie a loop on one end. Thread the yarn through the hole in the bottle cap so that the knot is on the inside of the cap.
Love the clever no-watering system!