That's one of the many interesting things about this game - you have lots of choices! And those choices can be difficult, sometimes! Another interesting thing is that the game allows you to experience the full consequences of your choices!!

The reality is that there is only a finite amount of food on the farm with each crop cycle. Once the current crop is gone, you could put every villager you have on farming and they still won't be able to harvest anything until the next crop matures. They can plant and water, but the crops still have to grow - and that takes time.