Having spent some time creating a smart home around homeassistant, I naturally placed a couple of sensors around the house and the garden. The Gardena Soil sensor must be one of the worst yet. Without watering and in bright sun light the soil humidity went up 10% today, while it registers the soild temp at 49°C now while the air is around 20°C. Not even the wintergarden goes up that high, it is at 36°C.
That thing is useless
