Third Reality
Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z)
- Zigbee2MQTT / ZHA
- Local control
- Zigbee
Prices verified September 2026
Our verdict
A £15-ish Zigbee probe that's cheap enough to put on every houseplant you'd actually be upset to lose. It pairs straight into ZHA or Zigbee2MQTT with no hub of its own required beyond a Zigbee coordinator you likely already have, and it exposes moisture and temperature as two separate entities — which is what makes it useful for automations rather than just an app widget. We used it to drive a three-times-daily watering reminder over Alexa and phone push; full build in the review.
What can Home Assistant control on the Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z)?
Home Assistant slugifies the Zigbee device name into entity IDs, so naming the device clearly at pairing time (e.g. 'Living Room - Plant Monitor - Monstera') avoids a rename pass later — you'll get sensor.living_room_plant_monitor_monstera_moisture and _temperature. No cloud account or vendor hub needed at any point; it's a ZHA/Zigbee2MQTT device like any other Zigbee sensor.
Specs
| power | Battery (CR2032-class), battery% reported to Home Assistant |
|---|---|
| sensors | Capacitive soil moisture (%) and ambient temperature (°C) |
| connectivity | Zigbee 3.0 |
| entities exposed | Moisture sensor, temperature sensor, battery, firmware update sensor, calibration offset numbers, identify button |
How does the Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z) compare?
| Product | From | Protocol | Local control | Integration |
|---|---|---|---|---|
| Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z) (this product) | — | Zigbee | Yes | Zigbee2MQTT / ZHA |
| Gardena Smart Irrigation Control (19032-20) | £251.69 | Bluetooth | Yes | Works with HA |
| Third Reality Smart Watering Kit Pro (3RWK0148Z) | — | Zigbee | Yes | Zigbee2MQTT / ZHA |
Frequently asked questions
- Does the Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z) work with Home Assistant locally?
- Yes. The Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z) is controlled locally in Home Assistant through Zigbee2MQTT or ZHA (ZHA / Zigbee2MQTT), so it keeps working if your internet connection or the Third Reality cloud goes down. Control and state updates stay on your own network.
- Which protocol does the Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z) use, and do I need a hub?
- The Third Reality Smart Soil Moisture Sensor Gen2 (3RSM0347Z) uses Zigbee. To pair it with Home Assistant you need a Zigbee coordinator (for example a SkyConnect/ZBT-1 or Sonoff dongle) attached to your Home Assistant host. Third Reality's own hub is not required when you integrate through Zigbee2MQTT or ZHA (ZHA / Zigbee2MQTT).