Do you have any reference designs, evaluations boards, or application notes for integrating the soil moisture sensor probe to larger systems?
For an evaluation board see our VG-RELAY boards. This simple board allows you to interface a single soil moisture sensor to valves, home automation systems, and sprinkler systems. It has a resistive thumb wheel so that you can easily set the trigger point. Boards are available which switch a relay on when the soil is too wet, or on when it is too dry. See our Application Notes.