Outdoor Plug Schedule Duration/Increment Feature

Would love a feature to be able to turn the plug on for a duration at increment. An example of what I refer, to be able to have it On for 15 minutes, off for 15 minutes during a 24/7 period. Another example on for 30 minutes every hour. Which would be great for controlling hydroponic watering control. [Which I am using my outdoor plug for]

[Mod Edit]: Title Modified to Enhance Search Clarity.

Is that not already possible?
create a rule to turn off the plug 15 minutes after the event of a turn-on and create a second rule that turns the plug on 45 minutes after the event of a turn-off.
I think that should work.
I have setup one rule that turns a plug off 2 hours after turn on and use that to disconnect a charger after i manually turn it on, that works, so i expect that the second rule will work too. You will get a warning when you create this rule as the trigger event and the target are the same device, but I did not find any problem apart from the warning.

Not sure I completely follow, as in both local schedules & via app rules, both request a start time, apart from adding 48+ rules (which I have for now), how would I create just 2 rules that continue to trigger every hour throughout the day?

Side note, the outdoor plug apparently limits to only 5 local schedules, so having to use the app rules which would be a problem is ever loose internet.

For instance for plug1
-Add a rule,
-select device trigger
-select plug1
-select when plug has been on for 15min
-select device action plug1
-select turn off