Berry farming is way too easy and not grindy enough for an MMO environment   my suggestion is to implement a feature where you have to use a fertilizer to make your berries grow, and this fertilizer is made by grinding together 12 thick clubs using a special machine.   To access this special machine you must have permission from the Berrymaster.   To get permission from the Berrymaster you have to complete 20 quests for him.   Each quest will involve either finding a set number of items