If I would do this automation then I would not rely on a delay since that will break at some point.
If that is a intentional reboot of HA or upgrade, or short power out on just the HA machine.
It’s just not a good solution.
Since you want the plants within a humidity range then you could easily set up a hygrostat and have this do the watering.
If you want the schedule also then I suggest you use a schedule entity.
With these two set up you now have two nice interfaces to set the schedule and the humidity.
Lastly you just create an automation based on the schedule and have it turn on/off the hygrostat.
This is a far better automation since it does not rely on a delay and it has a nice UI where you can change both the time and humidity, and it should turn on/off even if HA has just restarted.