Subsurface Irrigation

Six-year old lawn with subsurface irrigation, photo courtesy of Jim Bermingham

Jim Bermingham, who has had astounding success with the subsurface irrigation system he installed under his lawn, described his experience in a Los Angeles Daily News report as follows: “I have found great success with drip irrigation underneath the entire lawn. The only drawback I have is an invading gopher that chews on the water lines.  My ‘drip lawn’ has been installed for about six years now  and I remain very happy with it. It continues to look great but I do top dress it with a little bit of Milorganite (6-4-0 organic fertilizer) once a month and hand water over the Milorganite when I do so. Please note that you must use dripline with copper-infused emitters since copper prevents roots from growing into and clogging emitters. If I wasn’t happily retired, I would certainly create my own business installing drip systems for lawns.”

Currently, you can acquire 500 feet of Netafim copper-infused subsurface dripline for $177 through online vendors or 50 feet of a comparable Rainbird product for $22 at home improvement centers. You can choose emitter spacing within the dripline of 12″ or 18″, while spacing between dripline rows is recommended at 12″ to 22″ depending on the soil; the heavier the soil, the farther apart the rows. Install the dripline 6 inches below the final grade and you will be able to aerate your lawn to a depth of 4 inches. You can utilize the same copper dripline, whether on the soil surface or below it, when planting shrubs and ground covers.

I recently saw subsurface irrigation tubing being installed for a landscape of shrubs and ground covers in a commercial shopping center, and I think it is fair to say that subsurface irrigation may be in all of our futures. Not only does less water need to be applied because it goes directly to the roots, but evaporative water loss from the soil surface is eliminated.