I am satisfied with using moisture sensors from Yookr.
Among other things, by properly calibrating the sensors, I find that the soil and tree aggregate readings are correct, at various soil types and aggregates.
The dashboard is user-friendly and clear with colours green (= good), orange (= warning) and red (= too dry/too wet). We will receive an alert email when the limit is reached.
Furthermore, Yookr has a good and quick helpdesk for questions.