A low power, autonomously programmable plant watering device for custom irrigation regimes of individual plants. The device has an integrated sensor that quantifies soil moisture. The device initiates watering by opening a magnetically sealed valve in response to a soil moisture measurement that falls below a preset threshold. The device can terminate watering by closing the magnetically sealed valve in response to a soil moisture measurement that meets or exceeds a preset threshold and/or at the expiration of a preset time interval. The device utilizes control system comprised of a microcontroller and an embedded application or applications to initiate moisture sensor readings and the opening and closing of the magnetically sealed valve. The valve is opened when the control system actuates a small motor that engages a Hall Effect sensor system with an articulated member having a reference magnet used as an open-closed valve status indicator and a strong magnet that is moved into a position to unseat a magnetically seated valve stop.
