US Patent 8660705 Irrigation system with soil moisture based seasonal watering adjustment

A soil moisture based irrigation system includes a stand alone irrigation controller with a seasonal adjust feature and a stand alone weather station including at least one soil moisture sensor. The soil moisture based irrigation system further includes a stand alone soil moisture control unit operatively connected to the irrigation controller and the soil moisture sensor. The soil moisture control unit includes programming configured to calculate an estimated soil moisture requirement value using a signal from the soil moisture sensor and to automatically modify a watering schedule of the irrigation controller through the seasonal adjust feature based on the estimated soil moisture requirement value to thereby conserve water while maintaining plant health.