Garden/Greenhouse monitoring

[tupperck]

Initially, my rough thought for a system like this is essentially what is shown on that garden-bot site: a pc in the house tied to sensors out in the garden for soil conductivity, soil temp, RH, and temp at the bare minimum. Other features I would like but are not strictly necessary include a water valve controlled by the system, and a way to open the vents in the greenhouse when it's getting too hot inside.

It seems like Raspberry Pi would be an ideal control station for the whole system. Is it possible/simple to build a sensor station using an Arduino and necessary sensors, and then tie that (wireless?) to a RPi that is used to control the whole system? The controller and sensor station would only be about 12 feet from one another, through one exterior wall. I like that the RPi would give the possibility for a gui without needing to have a dedicated PC in my house just to do the gardening stuff.