How do I build an app in blynk that can get notification of Soil level in the farm and send a notification to the user
You’d connect your soil sensor(s) to a microprocessor which runs software that talks to the Blynk server and sends a notification if certain criteria are met.
If you want to use GSM as your connection type then you have the option to add a GSM board (maybe in the form of a ‘shield’) or to use a device like the TTGO ESP32 GSM device that has everything built-in.
Pete.