You can always visit the farm at the lobby to grow plants and get certain ingredients or just to feed your pet. You can travel to the farm by typing /farm in the chat.
Food is used to gain XP to your pets and level them up to get more skills/bonuses!
During the MELON BOMBER Event, you have a +1 yield chance from ALL plants. YES! EVEN BERRIES!
Your class will automatically change to Farmer class when you start planting seeds.