A plurality of wireless transmitters tethered to a plurality of soil moisture probes, each of said probes having first and second elongate conductive materials encapsulated in a non-conductive substrate, coupled to a power source and configured to be placed in the soil to form a capacitor. An irrigation control box is equipped with a receiver and a processor coupled to a plurality of irrigation control valves, each irrigation control valve corresponding to an irrigation zone wherein at least one probe is placed. The processor converts signal data received from the plurality of transmitters into a soil moisture value and (i) opens a control valve corresponding to the zone to which the probe corresponds upon detecting that the soil moisture value in the zone has dropped below a threshold value and (ii) closes the control valve upon detecting that the soil moisture value has raised above a threshold value.
