As we turn the corner into summer, irrigation systems become a more talked about topic. They are certainly a luxury amenity and, when designed and managed properly, can provide a homeowner or property manager with some peace of mind that landscape investments will not be lost to the whims of weather. Unfortunately, I frequently consult on properties with irrigation systems that aren’t being managed well and, in many cases, are producing more harm than good. I’ve listed below a few simple maintenance tips to consider as we dive into June.
Monitor your system regularly. There are a lot of moving parts that can be damaged by mowing, bed maintenance, even animal behavior. Adjust run times seasonally and be sure the system is deactivated properly before freezing weather. When monitoring your system, walk through each zone. Look for malfunctioning heads, poorly aimed spray throws, or obstructions caused by plant growth. Be sure the system’s rain gauge and/or moisture sensors are operating.
Water in the morning, preferably before 10. This schedule, though it will duplicate dew hydration, will help avoid disease that evening/night watering can help instigate.
Conserve. No area of your lawn should require daily watering. It isn’t about frequency, it’s about thoroughness and weaning your plants off mechanized irrigation. Surface, or “light” watering produces shallow roots, reducing your turf and ornamentals’ drought tolerance. Less frequent but more thorough watering is best. Think 4- to 6 inches deep for fescue lawns and approximately 12 inches for woody stem ornamentals and trees. This sounds good, but how do you know when you’ve achieved the goal? A probe test — done with a tool that can pull a small plug of soil several inches deep — is best but you can use a hand trowel as well. Within a few minutes of an irrigation station shutting off, use a trowel to pull away the top few inches of soil in the newly watered area. If the top grade isn’t muddy and the subgrade (back to the 4- to 12-inch depths) is moist enough to be rolled into a cigarette shape, things are good to go.
I shouldn’t leave this topic without noting that thorough watering goals aren’t achievable in some soil circumstances. Where porosity is an issue, the No. 1 goal should be to avoid runoff. It’s simple: too much water can be as bad — or worse — than too little. When runoff water (irrigation supplied more rapidly than soil’s absorption capacity) is noted, consider replacing nozzles or reducing run times and continue to monitor. Call in a landscape professional if plant health is affected.
If you’re in the process of designing/remodeling a landscape, ask yourself or your design professional if an irrigation system is even necessary. Be sure to arrange plantings in hydrozones that require similar amounts of water. Reduce grassy areas in favor of more naturalized spaces featuring natives that are adaptative to Middle Tennessee’s weather patterns. Think of the grass lawn locations as “area rugs” instead of the dull “wall-to-wall carpet” lawn designs of the early suburbs.
If you’re willing to provide some garden hose assistance getting your new landscape established and don’t mind a little summer dormancy discoloration in your fescue, you can save the expense of an irrigation system and, in turn, do the planet a favor by conserving your share of the nearly one-third of all U.S. household water that’s consumed on our lawns (epa.gov).
Dr. Ernie Reynolds’ award-winning work is enjoyed in public and private gardens throughout Middle Tennessee and beyond. His firm, Holly Consults, represents residential and commercial clients as managers of landscape and exterior construction projects of all sizes and complexities. He can be reached at .