It might be cleaner to save the plots with whats planted, with rotation(or take out rotation, I don't see this as needed, but please explain your specific use if its actually needed(if you need assistance with it)) and time.
You would have to be careful about the time aspect, if you save a plot as planted at 3pm on 1/1/2017, and they immediately close the game till 1/1/2018, it will still be fully grown(or dead if that is a feature) when they open it back up.
If you want real time, great. If not, you will need to save the variable with how long its been planted(which will only tick away when the program is open)