After some modifications, the project is online again. The main problems with the project was the cheap modules from ebay failed miserably on long run. When the soil sensorts started rusting after one month, they became instable. The buck converter and a BMP280 sensor died. Fortunetly, the email warnings worked and i was able to save the ESP and the PRO mini.

The version 2 is on the way, with properly designed PCB and mutch more reliable modules.