I would like to know how often that I should water my flower garden.

My understanding is that I only need to water my lawn once a week, as
long as I add at least one inch of water when I water my lawn. Of
course I need to water more often if the weather is hot and dry or if
I have added grass seeds. I am wondering whether I can apply the same
approach to flower garden watering.

I am asking this not only to learn the frequency of watering, but also
to determine if I need to use an automated watering system for the
flower garden. If I only need to water once a week, I can easily do
this manually without using an automated system. If I need to water as
frequent as every other day, I think I am better off using an
automated system.

(I know that I need to water plants in a flower box as frequent as
every day. But I am not asking about flower box here. I am asking
watering plants in a flower garden on real soil).

Thanks in advance for any info.

Jay Chan