In case, if you feel that you will be gone for some time , like going to school
or bed, then have all the adult Sims plant no matter how long it takes. Make
certain that they all are motivated as they will make 1.5x amount of
Simoleons. Allow the babies to sleep and allow preteens & toddlers to watch
movie marathon.
While you are sleeping, make your Sims do some work like gardening and
stuff. If you garden around seven or eight hours crops during night, you
would wake up with huge number of XO & Simoleons.