The decision on how far to plant the sensor does not affect its ability to collect data from the soil. Rather, it is a question on the data you want to collect. 

In terms of the plant, it is common practice to install the sensor within the root zone of the plant. Therefore, the depth of installation should be adapted to the depth of the roots of the plant you wish to monitor. 

Measuring within the root zone yields information on when to irrigate. The data you get from these measurements will indicate when irrigation is neccessary.

Measuring at the lower edge of the root zone yields information on how long to irrigate. 

For optimal irrigation, sensors in both lengths (to measure within and at the lower edge of the root zone) is advised. If only one length of sensors is available to you, going for the center of the root zone is advised in order to monitor the water potential and to know when to irrigate. 

In terms of the distance of installation from the plant, there are two factors that should be kept in mind: 

1. Distance from the plant: In order to stay within the root zone, the distance from the plant should be chosen according to its root radius. In order for the measurements to be accurate about the plant(s), the sensors should be planted within its root zone.
2. Distance from the dripper: To get the best results it is common practice not to place the sensors too far from the dripper either. Here, 5-10 centimeters (2-4 inches) are good practice.

Did you know that Valenco offers different lengths of sensors (15, 25, 55 and 85 cm) in order for our customers to be able to collect data of their soil from many different depths? Feel free to reach out to info@cital.io to speak to a representative about the different options.