BERTAUSKI COLUMN: Watering lawns just got smarter

Soon, we won't carry a smartphone. It'll be a chip embedded in our brain. We won't need to memorize facts, we'll download them. We'll text message like mind readers. Smartphones will do the thinking for us. A new generation of irrigation controllers, or smart controllers, is doing exactly that.

January may seem like an odd time to discuss irrigation since most plants are dormant and need very little supplemental water. However, there are many systems out there running on a summer program that operates every other day. And trouble is sure to follow.

Irrigation systems can do more damage running right now than if they were just turned off. In some cases, an irrigation system just isn't necessary.

Too much water reduces soil oxygen, which roots need to function.

Too much water can result in shallow roots since root systems do not have to grow deep to access water. Shallow roots mean less stress tolerance to heat.

Too much water also can mean more disease. Wet foliage encourages leaf spot disease and saturated conditions can lead to root rot.

Irrigation schedules will vary, depending on the weather and the plants. In arid climates, such as Arizona, many residential landscapes will not survive without supplemental irrigation. This is not the case with the Lowcountry.

Plants need to be watered during the first year after planting. In the summer, water may need to be applied daily because the root system is so limited.

The primary reason why plants fail during establishment is water-related, either too much or not enough. Once established, lawns only need water during extended drought. After a few years, well-established shrubs need very little irrigation and trees need none at all except during very extreme drought.

In theory, good irrigation practices only replace the water that is lost to the atmosphere through evapotranspiration, which is mostly affected by temperature and humidity.

In the hottest part of summer, the Lowcountry loses about 0.2 inches of water every day. Under these conditions, it takes five days to lose 1 inch of water.

In summer, with no rain, a typical irrigation system would run every other day to replace a total of 0.4 inches of water. In order to do that, rotary sprinklers (a single stream that rotates back and forth) should run about 20-30 minutes each time and sprayheads (pop-ups that spray a fan of water) about 10 minutes.

In the winter, an irrigation system running a summer schedule produces too much water and can damage root systems. In a dry winter (like we're in now), you may need to water once every two weeks.

Occasionally, I'll see irrigation systems running every other day throughout the winter. Maybe the home-owners forgot to change the schedule. Or maybe they just don't understand how to work the controller or even where it is.

Technology to the rescue.

Smart controllers automatically adjust the irrigation schedule based on weather conditions, soil type and plants.

Some smart controllers, such as the Hunter Solar Sync, are modules that can be plugged into an existing controller to monitor weather and alter programs.

Other smart controllers, such as the Rainbird ESP-SMT, are self-contained units that do everything. Homeowners will not need to change the programs since the smart controller helps prevent overwatering and conserves water.

As you can imagine, smart controllers cost significantly more than conventional controllers. Many smart controllers cost a couple of hundred dollars as opposed to $30 for a basic controller with no bells or whistles.

Smart controllers can reduce water consumption by 15 percent to 30 percent. While these savings may not be recouped over the life of the irrigation system, the irrigation practices will significantly improve the life of plants and lawns without the homeowner having to understand anything about evapotranspiration.

The Irrigation Association has a great resource that evaluates various smart controllers.

To purchase one, ask an irrigation contractor or visit www.sprinklerwarehouse.com.

Tony Bertauski is a horticulture instructor at Trident Technical College. To give feedback, email him at tony.bertauski@tridenttech.edu.