Schedule Duration and Soil Moisture

I have a question about soil moisture and schedule duration and how they work together.

I have 9 zones and it’s been a hot and dry summer here in southern California. My schedules have been running too late into the day, i.e. 12PM, 2PM, etc. I thought I would modify the schedule duration by cutting them all in half. Changing the duration has had the desired effect with respect to completion times. However, when I check the soil moisture for each zone, it says 99% which cannot be accurate. I’ve cut the watering times in half and expect the soil moisture to reflect that.

Does the Rachio scheduling assume that a completed schedule equates to a zone filled to capacity? I would assume that the zone moisture capacity would be a factor of nozzle inches per hour and run time (possibly other factors), but it appears that the Rachio algorithm assumes full capacity after schedule completion.

I’d like to understand how zone capacity is calculated so I can figure out some other way to address my long run times.

Edit: I’m using Flex Daily schedules.


This depends a bit on how your reduced the watering time. If you simply changed the TIME, you’re telling Rachio that it will apply the water Rachio calculates that it wants to apply in less time. So it will think it’s still getting the same amount.

Zone Capacity is simply Available Water x Root Depth x Allowed Depletion. An example:

  0.17 x 6" x 0.50 = 0.51"

To do what you want, IMHO, change the Allowed Depletion. This will tell Rachio you want to water, say, half as much water at one time. Instead of keeping the moisture between 50% and 100%, it will then keep it between, say, 75% and 100% (with an Allowed Depletion of 25% instead of 50%). It will then water more often, so as to keep giving your lawn the total required moisture. In the above example, substituting 0.25 for 0.50 gives 0.255. Watch you don’t lower it TOO much, though, or even watering every day it may not keep up.

I just modified the duration in the schedule itself. For each schedule, there is a Duration category and I tapped on that and cut the time for each zone in half.

I have played with Allowed Depletion and I observed no changes in watering times, watering frequency, etc. I speculated that the Allowed Depletion needs to be set before creating the schedule but I never did much triage with this issue. Perhaps it was a bug at the time. I have not tried this in a while and will try again.

Thanks for the information. I appreciate it!

That’s what I figured. If it were me, I’d go back to the Default values and start from there.

It’s kind of confusing. I just changed Allowed Depletion on my drip zone, wanting it to water less at a time but more often. When I then looked at the Drip schedule (I have a separate schedule just for drip zone - still playing with it), it showed the same time to water, as did the inches of water on the graph. I had to Open the Drip schedule, hit F5 on my PC to have it recalculate, at which time the time changed, and going back to the zone, the water applied changed too. Sometimes things don’t update when you think they should.