If it is in only half-sun, you may be overwatering. If it were in full sun I could see watering every day (Depends on the size of the pot too, of course). Check first; sometimes I lift my pots a bit to see how heavy they are with water. Or stick your finger deep into the soil. While half-sun would not cause the flowers to wilt and die, they certainly appreciate more sun than that. Six hours of direct ought to keep them happy. How is the humidity?