The number of crops you plant depends of the amount of energy you have. You can either plant Eggplants or Potatoes. Eggplants are harvested after two hours while Potatoes are ripe after four hours. Either way, you’ll have full Energy when it’s harvest time.
Another source of Food is trees. You should invest in Peach Trees. These are harvested every three hours. A single Peach Tree earns you four Food per harvest. The Peach Collection also rewards you 7 Energy when completed.
When you’re done for the day, plant Sunflowers. You harvest it after 18 hours and you’ll gain 3 Food per crop. Plus when you turn in the Sunflower Collection, you’ll be rewarded with 8 Energy. Other collections that reward Energy are Peach (7 Energy), Groundhog (4 Energy), Chicken (4 Energy) and Cherry (3 Energy).
Another source of Food in Frontierville is the bonuses posted by your friends. When your neighbor clobbers a groundhog, they have the option to share a reward. Be on the lookout these rewards in your wall.