Drip irrigation pipe comprises drip irrigation emitter units bonded thereto, the pipe being made of water-impervious material and having foamed closed-cells therein. The drip irrigation pipe may be used in a piping package comprising also a spool. The length of the pipe and the number of the emitter units in the package are greater than those which the package of the same weight with the same spool would have, if the pipe was made of the same material but not foamed, and had the same outer diameter and about the same thickness.