a few things I think would be nice. 

• a float similar to the voltmeter for water level in ponds.
• something to either create or purchase seeds for fully automated farms.
• an automated hand pump for unlimited water. ( maybe high power usage for balance?)
• adjustable time scale. ( I want the game to be even more idle, 4 hour pumpkins is my dream)

I love the game as is, but I hope you keep developing this, I would pay 5$ again for a mobile version.