Irrigation timers key to plant's success

The secret to a plant's success is efficient watering. The secret to water-efficient landscaping is a good irrigation timer.

I found this out the hard way after we recently replaced an old timer with a new one. The old timer gave us great flexibility in setting up variable watering times and days. The new timer is pitiful in its lack of versatility. Because we didn't buy a quality timer in the first place and pay a bit more, we now have to replace the timer again, wasting more time and money.

Some irrigation controllers allow the operator to determine when and how long to water. This is an open-loop system. A clock is used to control the system and must be reset as the weather warms or cools, or when it rains. These systems are relatively inexpensive and readily available.

Closed-loop systems depend on sensors that measure soil moisture, temperature, radiation, wind speed and relative humidity to provide feedback for computers that make decisions on when and how much to water. They respond automatically to changing environmental conditions and water only when necessary. They can be complex and initially costly. Some of the computerized versions operate through a satellite system and require a monthly or yearly fee for the satellite service.

Most home irrigation timers are clock units that allow specific watering schedules to be implemented. They usually have a calendar selector that allows you to set which days you want to water. You can also set the start and end times for each station. If you put the system in a "manual" operating mode, you can ruin the irrigation system without disturbing the preset watering days and times. A station omission function allows you to skip specific stations during the next irrigation cycle.

A timer that has more options gives you more control of your landscape's irrigation. In an arid environment, this extra control saves water. We need flexible systems that allow us to provide specific plants with only the water they require to be healthy, rather than inflexible systems that result in us overwatering some plants and underwatering others. For example, established trees rarely need daily watering; deep watering is much better. Perennials are often shallow-rooted and may need frequent irrigation. What a waste of water to irrigate our trees daily, if only our flowers require daily watering! It is best to manage lawn irrigation with a separate station designated only for the turf.

Make your landscape water-efficient, keep you plants healthy, and protect your landscape investment. Make sure you have a quality irrigation timer that provides you with the flexibility you need.

For more information on watering and gardening, contact me, 887-2252 or skellyj@unce.unr.edu, or your local University of Nevada Cooperative Extension office. Check out many useful horticulture publications at www.unce.unr.edu. "Ask a Master Gardener" by e-mailing mastergardeners@unce.unr.edu.

• JoAnne Skelly is the Carson City / Storey County Extension Educator for University of Nevada Cooperative Extension.