With the Aquaflex from Truebner you can measure soil moisture and average temperature over a large area.
The average soil moisture is measured along a 3 m long special measuring cable. In contrast to point-based sensors such as the SMT50 or SMT100, the moisture is recorded in a very large measuring volume. Individual accidentally wet or dry spots, e.g. when watering lawns, are no longer a problem. The AquaFlex sensor is ideal for easy installation under turf or for subsequent installation in an existing lawn. The special measuring cable has a robust polyethylene jacket and is practically indestructible. With special calibrations, this sensor is also suitable for use in construction technology.
Available here in the shop:AquaFlex lawn moisture sensor

