Using a simple Arduino computer ($20 microprocessor) you can monitor things like water temperature, pH, nutrients, etc. and you can make adjustments all from an iPhone. You can also take pictures of it just to keep an eye on it no matter where you are in the world.
As far as commercialization, you toy with the idea of managing home-based food systems for people all using an automated and system that would manage everything. This same technology is currently being applied in commercial greenhouses management and monitoring and there's still a lot of opportunity there in my opinion.
Create an application that crunches big data sets in order to gauge supply and demand for various types of produce over the coming year or two.
Agriculturalists could use this information to decide on the most profitable crops and product.
This is not an old idea and has been executed successfully by those who have a grasp on differentiation for a long time.