Winter Irrigation and Lawn Care

Winter Irrigation and Lawn Care

When your lawn goes dormant in the winter, don’t neglect it until spring — it still needs care and attention. One of the most important factors in winter lawn care is irrigation.

Winter Irrigation

Winter irrigation prevents grass roots from drying out, and keeps them healthy for strong growth in the spring. It also helps safeguard the roots from freezing temperatures. The water acts as an insulator, and root cells full of water have a better chance of withstanding the cold. Further protection is added by the moist soil, which tends to stay warmer than dry soil. 

When to Water

Your lawn doesn’t need as much water in the winter as during the warmer weather. Water once or twice a month when there’s not enough rainfall using the cycle and soak method that allows water to penetrate the root zone.

Other tips for winter irrigation:

  • Water only when the temperature is above 40°F, and there’s no snow or ice on the ground.
  • Water a day or two before a forecast freeze. 
  • Water earlier in the day so the lawn can absorb it before the temperature drops at night. Moisture needs time to evaporate off the blades during the day, minimizing the possibility of fungal growth.
  • Water only your lawn, not sidewalks and roads where runoff can form ice.

Winter Irrigation Help Using Controllers

Your standard controller has a feature to help with winter watering. Use the “seasonal adjust” setting to change the zone run times to a percentage of the warmer weather schedule. As well, you can convert your controller into a “smart” one by installing add-on sensors that monitor and regulate irrigation based on weather and soil conditions.

Add-On Sensors

Rain Sensors shut down your sprinklers when it starts to rain, although some models are adjustable to allow specific amounts of rainfall before turning off your system. In Texas all new automated systems or replacement controllers must include a rain sensor approved by the TCEQ (Texas Commission on Environmental Quality).

Freeze Sensors, sometimes combined with rain sensors, turn off your sprinklers when an adjustable temperature is reached. 

Weather-Based Controllers

Weather-based irrigation controllers are also known as smart or evapotranspiration (ET) controllers. Evapotranspiration is the combination of evaporation from the soil surface and transpiration by plant material. Calculations using ET data make it possible to determine watering needs for specific landscapes.

Weather-based controllers automatically change irrigation schedules and watering requirements based on local weather conditions. When programmed correctly, these controllers need very little intervention.

There are three categories of weather-based smart controllers, based on the type of weather data they use: historical, on-site, and signal-based.

Historical

This controller typically uses pre-programmed historical ET data to determine watering time for your area. Usually the watering time is reset on a monthly basis. You may need to manually override the automatic controller settings if they’re not matching the current weather conditions.

Some historical controllers can further adjust the irrigation schedule with more accuracy by using a sensor — usually a temperature sensor.

On-Site

On-site weather measurement controllers use data collected from on-site sensors to calculate ET measurements for irrigation adjustments. Sensor equipment may include rain and temperature gages, soil moisture sensors, and mini-weather stations. Many sensors are now wireless, making them easier to install.

Signal-Based

Signal-based controllers receive weather information on a regular basis using telephone, radio, cell, cable, web, or pager technology. Local weather stations that collect evapotranspiration data usually send the signals, and often there’s an annual service fee. Without the signals the controller will operate like a standard one and won’t make automatic irrigation schedule adjustments.

With signal-based controllers there are no on-site sensors to maintain or replace. The higher-end controllers have extras features, such as online programming, leak detection, and email alerts.

Lawn Care

When to Mow Your Lawn in the Winter

Even though your grass goes dormant, it will continue to grow when the temperature goes above 40°F. If the winter is moderate, you might need to mow your lawn monthly. Mowing increases the density of the grass, and will kill most common winter weeds. Be sure to use the mower bag attachment to prevent re-rooting of weeds from seeds.

To help insulate the root system, raise the mowing height to the maximum for that type of grass. Mowing heights for popular Austin area grasses:

Zoysia — 1.5 to 2.5 inches

Buffalo — 2 to 4 inches

Bermuda — 1 to 2 inches

St. Augustine — 2 to 2.5 inches

Definitely don’t mow the grass when it’s frosted or frozen. The crowns (the area right near the base of the blade protruding from the soil), can be damaged or crushed, preventing any growth in the spring. Walking on frozen, brittle grass also causes the same damage.

Overseeding for Green Winter Grass

The grasses that go dormant in the winter are warm-season grasses, such as St. Augustine, Buffalo, Bermuda, and Zoysia. If you want green winter grass, you can overseed with perennial or annual cool-season ryegrass. Both perennial and annual ryegrass should be seeded in October and early November, at least thirty days before the first frost.

Annual ryegrass lives for a season, then dies off in the spring to make way for the return of the warm-season dormant grass. Perennial ryegrass survives permanently in colder climates, but also dies out in climates with hot weather in the spring. Many lawn care professionals prefer the perennial ryegrass because they like its lush, green appearance.

Winter grass will have to be mowed on a regular basis, usually once a week. Mow it to the recommended height of your permanent grass. Annual ryegrass needs to be cut more often, especially in the spring, and can become unmanageable if not done regularly.

Can I Overseed With Water Restrictions?

Overseeding isn’t recommended in areas with water restrictions, as ryegrass needs frequent watering until established, followed by watering at least once a week. However, some homeowners have overseeded winter grass successfully by sowing the rye seed the day before their designated watering day. The next day, the irrigation was used for both the new seed and the dormant lawn. Each week, the homeowners irrigated on their designated watering day, with fall and winter rain acting as supplemental watering. Although occasionally the seed was a bit slow to germinate, the winter lawns turned out great.

Your sprinkler system is an important investment. Call Smart Earth Sprinklers at (512) 694-1147 for all your inspection, repair, and maintenance requirements.

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