Winter watering for Colorado lawns: when and how

Why Colorado lawns need winter water

CSU fact sheet 7.211 describes fall and winter along much of the Front Range as dry air, low precipitation, little soil moisture and swinging temperatures, often with little or no snow cover from October through March. Roots can be injured during these long dry spells. The damage often doesn't show until late spring or summer, when weakened turf thins out.

New lawns, whether seeded or sodded, are most at risk. So are lawns with south or west exposures, sites that get reflected heat from walls and fences, and windy spots. CSU notes lawns in warm exposures are prone to late-winter mite damage and that water is the best prevention.

The rules

• Water only when air and soil are above 40°F and there's no snow on the lawn.
• Water at midday so it soaks in before night freezing.
• Water during extended dry periods, about once or twice a month (7.211). CSU's lawn fact sheet 7.202 gives every four to six weeks as the minimum, when the ground is thawed and will take water.
• Focus on slopes, shallow soils and south- or west-facing areas.
• Don't create sheets of ice: CSU warns ice lasting over a month can smother or mat grass.

Practical setup

Most sprinkler systems are blown out in fall, so winter watering usually means a hose and a portable sprinkler. Run it, then disconnect and drain the hose so the spigot doesn't freeze. Check the soil temperature above, or open your ZIP page (for example 80013), and pick a calm, sunny day in the 40s or 50s.

Trees and shrubs need it too and are the bigger investment. CSU gives a survival rule of 10 gallons per inch of trunk diameter per watering for trees. For fall feeding, see fall fertilizer in Colorado.

Questions

Sources

1. Colorado State University Extension: Fall and Winter Watering (7.211)
2. Colorado State University Extension: Lawn Care Basics (7.202)

Soil temperatures: NOAA GFS model, 0–10 cm layer. Snow: NOAA and National Weather Service. See how we measure.