Farm them, you can plant like 5 a day depending on how long you play, etc. but 5 a day is pretty good.
Be sure to pay the farmers to watch them and also plant fruit trees in excess for more exp.
It depends. If you feel like there's a reason for you to have your farming up (quests, etc.) then you should farm them. If you're not interested, I'd just throw 'em in the G.E.