Abstract: A gravitational irrigation system is disclosed which uses preformed, water-impervious, flexible, collapsible, plastic tubing as a replacement for an open ditch. The tubing is laid in a shallow trench along the area to be irrigated and held in place by mounds of soil thrown on the top thereof. Annular apertures are cut in the tubing at intervals where exit of water is desired. Flexible, annular, open-ended spigots having a flanged end of greater diameter than the diameter of the body of the spigot are inserted, flange end first, into the apertures to form a laterally extending spigot from the tubing. The body of the spigot has an outer diameter approximating the diameter of the cut in the tubing. The flange of the spigot substantially seals against water leakage between the tubing and the flange of the spigot.