Weather stations estimate evapotranspiration (ET) to estimate crop water use for irrigation scheduling. Estimates of crop water use by subsurface measurements of soil water content have been limited by the high cost of reliable soil moisture sensors. Advances in electromagnetic sensors have made automated irrigation scheduling based on soil moisture sensing a reality. Our objectives were to: i) compare irrigation scheduling based on weather station ET estimates with those from a time domain transmission (TDT) soil moisture sensor, and ii) apply the HYDRUS-2D computer-based numerical model to simulate volumetric soil water content (θ) dynamics in the profile and any drainage occurring below the plant rooting depth. The TDT sensor connects to a custom irrigation controller or interfaces a small display/control box with a conventional irrigation timer where irrigation scheduling is based on a threshold θ value (θ_Thresh). The sensor controlled the irrigation by allowing the preprogrammed schedule to operate whenever the sensor-estimated θ dropped below θ_Thresh. The TDT sensor was installed under Kentucky bluegrass with a weather station providing estimates of ET for comparison over a period of seven weeks. Relative to ET-based irrigation recommendations, the TDT system applied 16% less water when irrigating with a sprinkler having an efficiency of 0.80, and relative to a fixed irrigation rate of 5 cm week^-1, the TDT system applied 53% less water. HYDRUS-2D modeling results of the TDT irrigation indicated no detectable water drained below the estimated 30 cm rooting depth when uncontrolled application events (rainfall) were ignored. The θ_Thresh value is soil-type dependent and was established considering θ at field capacity and permanent wilting point. The water savings with the TDT system is not only important to water conservation, but saves an estimated $5.00-$100.00 per month based on water prices in the US and a 1000 m² turf grass plot.