If you are finding 2 schools of thought, then there will always be a debate and no one can actually insist which is "right" or "best". ;-)

I have done both depending on whether my plant needs the water or not. If I find the soil dry in the morning, I'll try to get out there and water then. And if it is dry in the evening, I'll water at that time.

I think a big part of the issue of morning vs evening seems to actually revolve around overhead watering and wet leaves, where it's generally easier for the leaves to dry as the day progresses, which helps to reduce leaf diseases. Whereas watering overhead in the afternoon may result in leaves remaining wet overnight as the temperature drops and evaporation slows.

Of course there is the other school of thought that says that Mother Nature "waters" during the day and at night and plants do just fine, so what does it matter? Plus there is the issue of those who are in areas with very little humidity and adding moisture in the air via misting can often keep the plant's leaves from dessicating.

Depending on the plant, pot, it's positon in the sun, some of my containers get watered twice a day. Tally Ho!

I'd rather do it in the morning. This way the plants have time to soak up the moisture & can face the heat of the day. However during the week, unless I have a day off, it's not gonna happen. I get up at 5am & out of the house by 6. There is no time for watering. Morning waterings are for weekends & days off.
Since I get home at about 5PM or so, I usually get everything watered by 6:30. It's my "unwind time".
It takes me 45 minutes to an hour to water everything.
{{gwi:3119}}

Your garden is so lovely! I feel terribly guilty about my few plants outside. I work 54 hours a week (three 14 hour days) so I rarely got a chance to go outside and water. My poor plants dried up! I have two bleeding hearts and one hosta that got the worst of it...and I'm hoping that they'll come back in the spring, but if not, I'll try to get some more "drought tolerant" varieties for the days when I can't go water!