After I complete my Weather Station Project Idea (Ardrino) I will move onto this project.
Using temperature/humidity/soil moisture sensors and a tap solenoid (recycled) I could automate my greenhouse watering. The system will be internet aware with a control panel to override the sensors.
The 555 Timer will trigger update events and the 4 bit timer is really there to help switch open circuits to reuse the limited analogue pins on the Ardrino, EEPROM will save data if the internet is offline. I plan on open sourcing all code and designs.