ESPHome firmware for the LILYGO T-Higrow WIFI Plant Sensor

How to install esphome to the lilygo T-HiGrow wifi plant sensor

You can use the blue button “connect” below to install the pre-built firmware directly to your device via USB from your web browser.

Afterwards you can set up Wi-Fi and add your device to Home Assistant from this same web page. Make sure that it is on the same network as home-assistant is and it will connect automatically with the api of the plantsensor.

To enable the flower-card in home-assistant:

1. Get - OpenPlantBook API
2. Install HACS
3. Install Homeassistant Plantbook intergration
4. Install Homeassistant Plantbook api intergration
5. Install Homeassistant Flower card

How to Calibrate the LILYGO T-Higrow Wi-Fi Plant Sensor

Before starting, make sure you’re able to flash your sensor — otherwise, calibration won’t be possible.

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Step 1: Edit plantsensors.yaml

Open the plantsensors.yaml file and locate lines marked with:

# comment when calibrating

You need to comment out those lines. For example:

Original:

unit_of_measurement: '%' # comment for calibration

Becomes:

# unit_of_measurement: '%' # comment for calibration

Repeat this for every line that includes # comment when calibrating.

Then, locate lines marked like this:

# unit_of_measurement: "V" # uncomment for calibration

And uncomment them like so:

unit_of_measurement: "V" # uncomment for calibration

Repeat this for each similar line in the file.

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Step 2: Flash the Firmware

Once you’ve made the changes:

1. Plug in your T-Higrow sensor via USB.
2. Open a terminal and run the following:

esphome run LILYGO-T-Higrow-ESP32.yaml

You can do this through Home Assistant (ESPHome Addon), but flashing via your PC is usually faster.

While it’s compiling, grab a glass of water — you’ll need it later.

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Step 3: Get a Dry Measurement

After flashing:

1. Clean and dry the sensor completely.
2. Watch the log output. Look for lines like these:

[15:46:50][D][sensor:127]: '... Soil Conductivity': Sending state 0.07500 V
[15:46:46][D][sensor:127]: '... Soil Moisture': Sending state 2.83500 V

Write down the values — these are your dry (minimum) readings.

Let the sensor run untouched for 10 minutes, then confirm the readings are stable.

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Step 4: Update Your YAML with Dry Values

Open LILYGO-T-Higrow-ESP32.yaml and set the dry values you just recorded:

moisture_min: "2.83"
conductivity_min: "0.075"

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Step 5: Get a Wet Measurement

Now submerge the sensor up to the white line in water. Don’t go too deep.

Again, check the log output for readings like:

[16:22:22][D][sensor:127]: '... Soil Conductivity': Sending state 0.24400 V
[16:22:25][D][sensor:127]: '... Soil Moisture': Sending state 1.37300 V

These are your wet (maximum) readings.

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Step 6: Update Your YAML with Wet Values

Add the new max values to your config:

moisture_max: "1.373"
conductivity_max: "0.244"

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Step 7: Re-enable Sensor Filtering

Now that calibration is done, revert the comments in plantsensors.yaml. For example:

# Fertilizer sensor
- platform: adc
  pin: GPIO34
  name: '${devicename} Soil Conductivity'
  icon: 'mdi:flower'
  update_interval: ${update_interval}
  accuracy_decimals: 2
  unit_of_measurement: 'µS/cm'
  # unit_of_measurement: "V" # uncomment for raw data
  filters:
    - calibrate_linear:
        - ${conductivity_min} -> 0.0
        - ${conductivity_max} -> 100.0

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Step 8: Reflash the Calibrated Firmware

Reflash with:

esphome run LILYGO-T-Higrow-ESP32.yaml

You’re now running with calibrated sensor values!

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Bonus: Temperature & Humidity Calibration

If you’re using temperature/humidity sensors, open either:

• dht.yaml (for DHT11/DHT22)
• bme280.yaml (for BME280)

…and adjust the offsets in those files to calibrate them as well.