I've recently got back into gardening, particularly growing fancy Pelargoniums, and would quite like a way to monitor my potted plants, especially now winter has arrived, its a bit dark when I arrive home at night and it would be nice to instantly see soil moisture levels and have alarms to chide me into watering them.
Being a fan of feature creep (fan....or victim?) I've thought of a few nice add-ons to do, it would be good to monitor temperature and RGBW light levels as well, it would be interesting to see how the light levels and colours change throughout the year.
It will also be nice to have it wireless somehow, and energy harvesting if possible. Running wires to each plant doesn't really appeal if I can help it!
Waterproofing will also be a must, because plants need drinks too!
My Aquariumatic may be of some use to you buddy; just use different sensors to monitor what it is you need to monitor.
You could use the ESP8266 to add wireless to your project, either to feed data to another device on your network (such as your phone or a pc) or to feed data to an IoT site like thingspeak.
Thanks for the like, I'll check out your project, I'm just starting to get into ESP8266s for IoT.
Cheers