Zigbee and Wi-Fi sensors can work in a plant care system, but they are useful in different scenarios. Wi-Fi is easier to understand: the device connects to your home network. Zigbee requires a hub or coordinator, but is better suited for battery sensors and a grid of several inexpensive devices. The choice depends on scale, autonomy and whether local automation is needed.
If you have one Wi-Fi sensor in a room, a separate Zigbee hub may be unnecessary. If there are a lot of sensors, sockets, leaks, multiple zones and battery requirements, Zigbee is often more practical. The main thing is not to mix technologies accidentally, but to understand the role of each.
Autonomy
Battery-powered Wi-Fi devices typically use more power because connecting to Wi-Fi is harder on a small sensor. Some models solve this with infrequent updates, but then the data becomes less recent. Zigbee sensors are often designed for long battery life and short transmissions.
This is important for plants: the temperature and humidity sensor should update data regularly, but not require constant charging. If the device is located in a greenhouse or high in a box, frequent replacement of batteries quickly becomes annoying.
Network and coverage
Wi-Fi depends on the router and the quality of coverage. In a greenhouse behind a wall or in a box with metal, the signal may be weak. Zigbee is building a mesh network: devices powered by the network can transmit messages further. But this only works if there are routers on the network, and not just battery sensors.
Therefore, Zigbee requires planning. Placing ten sensors far from the coordinator and waiting for stability is a bad idea. First you need a hub, several routers and an availability check. There is an article about network roles roles of Zigbee devices in GrowerHub.
Local and cloud
Wi-Fi sensors are often linked to the manufacturer's cloud. This is convenient for a quick start, but worse for automatic watering and accidents. If the Internet is lost, local rules may not receive the latest data. Zigbee via a local hub or Zigbee2MQTT is easier to integrate into local automation.
For GrowerHub, the security logic must operate close to the devices. Remote access is useful, but leakage and pump stops should not depend solely on external service. Read more about this in the article reliability of automation without the Internet.
When to choose Wi-Fi
Wi-Fi is good if there are few devices, there is an outlet or power supply, you don’t need a mesh network, and the cloud application is fine. For example, one temperature sensor in a room or a ready-made device with a convenient API. Wi-Fi is also convenient for ESP32 and DIY projects where the developer himself controls the firmware and MQTT.
When to choose Zigbee
Zigbee is better for a variety of battery sensors, leaks, sockets, relays and areas where a network of devices from different manufacturers is important. It requires a hub, but provides a more convenient basis for local automation. The selection of devices for a greenhouse is discussed in the article Zigbee for a greenhouse.
Conclusion
Wi-Fi is easier to start with, Zigbee scales better for sensors and local automation. For GrowerHub, the practical choice is: Wi-Fi and ESP32 where DIY and power are needed, Zigbee for battery sensors, leaks and distributed plant network.