Mi Flora plant sensor

Product code: Mi Flora

Specifications

Bluetooth low energy (ble)
Powered by a CR2032 (3V) battery
Measures:
Soil moisture (%)
Soil fertility (uS/cm)
Light intensity (lux)
Air temperature (C/F)

After automating lights you'll get a need to automate more, so why not plants? I found the Mi Flora sensor online and because they are pretty cheap I thought it was worth the try. The idea is to stick the sensor in the soil and it will log the moisture, fertility and temperature. You can use the Mi Flora app or the plugin in the Mi Home app to read the results. In the app you can pick your plant and it will set all the ranges accordingly, but you can also set the moisture, fertility and temperature boundaries yourself.

The sensor is well built. The older versions are white, the newer version is green(ish) which does not stand out that much next to the plant. The inside is weather protected so you do not have to worry when you water the plant. The manual does state that you have to pay attention not to push the sensor too far in the soil, the plastic housing should be a bit above the soil, so I guess it is not 100% water proof. On the top is a light which indicates when the unit is synchronising, it can also blink on command from the app to see which sensor is which. The bottom of the sensor is a black painted circuit board which does the moisture measurement by capacitance. This is better than most of the DIY soil moisture sensors you see online because those will oxidise in time. At the bottom there are two metal pins which measure the soil fertility through conductivity.

Apps

You have multiple options to read values from the sensor. You can use the Flower Care app, or add it to the Mi Home app. The Flower Care app does have the possibility to update the firmware of the sensor, I was not able to do this in the Mi Home app.

Connection to it

The sensor communicates through BLE (Bluetooth Low Energy) which can be connected through your phone directly or through a supported Bluetooth hub like the Xiaomi Qingping Bluetooth Gateway or the Bluetooth capable Mi Hub. You can also make your own connection with an ESP32 and Home Assistant using ESPHome.
In the Flower Care app you can select a plant you wish to monitor and it will fill in all the ideal values it can measure. It then can notify you if one or more values are out of bounds. If you cannot find your plant by name, you can try the selection wizard and find the plant by answering a few questions. If that does not work you can alway set or adjust the values manually.

Power consumption

The sensor is powered with a 3 Volts CR2032 battery and can last a really long time. Most of the power goes to the communication of the unit so the battery wear will increase if you read the values often like through a hub. For me they are still running after three months connected to a Bluetooth gateway.

Measuring

The measurements look pretty accurate. The values look pretty much the same when you stick multiple sensors in one planting pot. For me most of the time I only look at the moisture because temperature or light is not something I can do about much (except for putting them in the right place in my house). The soil fertility is a value you can only depend on when the plant is properly watered because it is measured by conductivity. If the soil is dry it wil also say that the soil fertility is low.

Automation

Through the Mi Home app you can set automations for the measurements. There is a big missed opportunity because with the automations you can trigger with all the measures values, but you cannot use the plant parameters but have to set the conditions manually. So you can set an automation on the condition "Lower than the specified soil moisture", but then you have to set the value 0%-100% and not use the 20% set in the plant settings.

Branding

I saw a few models with different brand names like North. They are exactly the same but with different firmware. I was able to re-flash it through the Flower Care app and now it looks not any different than the other sensors.

Conclusion

For the price it is a well built little sensor and fun for a weekend project to make a sorts of automations. For example: you can switch on a grow light during the day if the sun is too weak or even water your plants automatic with some extra components. I had some fun with an ESP32 and connecting it to Home Assistant, I setup a Telegram bot which tells me which plants to water. But to be honest: it is just a gadget. I think it is much easier to just water all my plants at once, one or two times per week which takes far less time than looking at the app or notification, determining which plant needs water and then just water that plant, and repeating this step maybe the next day for a different plant.
But it is fun!

I bought mine from Banggood