Not sure if this is the right forum to post this in... but...
It would be very helpful to have the soil around a plant change in some way, even darkening, after being tended. If the plants havent been for x amount of time, they get that purple glow. So if a patch had been tended in the past x amount of time, it would be great to have the soil darken (look wet) or something. Just a thought. :)