Subsurface drip in grass

I have always tried to save water on my lawn irrigation. In every house I have lived in since 1995 I have installed subsurface drip in the grass areas. I always have to do this myself because contractors don’t want to do this installation. I bought the Rachio controller because of the flex daily schedule. However, after a 3 years I am really struggling to make it work with my drip system.

Proper watering of drip is different from sprinklers. To avoid root intrusion the area around the emitter should always be saturated. In order to do this the watering schedule should be everyday. See this link on a document by netafim []

I would like to be able to set the desired moisture level in the soil and the system calculate a different run time daily based on ET. Instead of skipping until depletion just calculate a different run time for each zone each day. The only time it would skip watering altogether is if the soil moisture content was above the necessary setpoint.

I feel you could use the flex daily as is except in my case instead of running a set time when the moisture is below a certain setpoint it would calculate a run time necessary to bring the moisture content from the current level to a desired level.

If there is a good way to do this with current software I would be glad to try, but to date I cannot figure out how to make it work correctly without manually manipulating run times constantly.

Try using a very small root depth (maybe an inch or two) on a daily flex schedule. If it is low enough, it should cause watering each (or almost each) day to replenish the root zone. I think the run time might be adjusted to refill the daily transpiration, which is what you are looking for.
Hope this idea works for you.

Thanks for the feedback. My experience is the run time never adjust unless there is a seasonal shift. If your saying it does then maybe there is a setting that is wrong. Would you have a clue what that setting might be?

With Flex Daily, run time never adjust period (short of setting changes), just interval. This is where it might be tricky if you need it to water daily. A VERY short root depth might kick flex into watering daily though, and chances are that the interval will never really change.