[semicolon_storm]

Water on the leaves isn’t bad if you’re watering in the morning where it’ll soon evaporate in the sunlight.

[cbsmith]

The evaporation is the thing you want to avoid.

[tuatoru]

I was told that water beads on leaf surfaces act as lenses, creating burnt spots on the leaves. So water at night.

[mapt]

This is 99% urban legend. You can just barely create it in a lab with just the right plant (with thick hydrophobic trichromes) under just the right light with no wind... but that's not what happens in nature.

[rvense]

I was told to water at night because it doesn't make much sense to pour water on the ground only for it to evaporate before it goes where it's needed.