From Bunni Wiki
As the cheapest food with medium regrowth rate, posie garden doesn't really satisfy the hunger of your creatures and could be considered ineffective.
A medium prized food, tulips garden have good regrowth rate and decent satisfaction for your creatures. Most of the time, tulip gardens are enough to feed the workers.
Very expensive food with high satisfaction but with a slow regrowth rate. It works well when combined with a batch of effective workers like Pandas (on mills) and Monsters.
Another source of food is the fruit from fruit trees.