The best time to install new soil moisture sensors is now, before the irrigation season starts. Sensors need some time to find equilibrium with the surrounding soil moisture, so ideally install two weeks before you need their data for irrigation decisions.
The Vinduino sensor station is designed for 4 low cost Vinduino soil moisture sensors. This allows soil moisture to be monitored at multiple levels, and with this data it is easy to figure out the best irrigation scheduling. For grape vines, the recommended sensor installation depths are one foot, 2 feet, 4 feet, and 5 feet.
We recommend using 1" PVC pipe to install the sensors at their desired levels. Keeping one foot of pipe above ground avoids wiring damage by wildlife.
Vinduino sensors measure the equivalent of soil water tension, the work needed for a plant to extract water from the soil. This is independent of the type of soil, and therefore easier to interpret than sensors that provide volumetric water content information.