Getting Enough Water on Flex Daily?

Hi, I am a lawn noob looking for some advice. I live in a house in Atlanta with Bermuda grass in the front and Zoysia in the back. When I moved in 8 months ago, I bought a Rachio 3 and configured all zones with zone type, spray head, soil type, exposure, and slope. Following the recommendations of the quiz, I set the schedule type to Flex Daily and let things be. But the Rachio is running very rarely, and I’m wondering if it’s slowly killing my lawn.

For some perspective, here is the history of the last 6 months:
May: Avg temp ~70F, total rainfall: 5.2”. Some zones ran once, some twice (total 5.5hrs)
June, July, August: Avg temp ~75F, avg monthly rainfall: 6.5”. All zones ran once a month (3.5hrs each time)
September: Avg temp ~73F, total rainfall: 4”. None of the zones ran at all
October: avg temp ~66F, total rainfall: 3.5”. All zones ran twice (7.5hrs total)
November (so far) avg temp ~55F, total rainfall: 0.8”. Nothing ran so far, with no runs scheduled for the balance of the month.

The grass looks yellowish green, and one of the trees looks like it might not be getting enough water. I’m starting to get concerned: could I get some advice on whether things are working properly or if I need to make some changes?

Thanks for reading!

Why not post the details / screen pic of one zone in here. It certainly sounds like you have misunderstood some setting and that is throwing it all off. The issue will be in the advanced settings

The majority of people can operate with default settings available water, allowed depletion (50%) and efficency (80%). You’ll likely set the root depth to 6".

So that just leaves the area which you surely can’t get wrong, and realistically the two most important items and the two that have the most affect on the watering frequency - the crop co-efficient and the nozzle inches/hr

If you have a spare zone on the controller, you could set it up as a dummy and amend setting from the real one and see the effects of changes are in the calculated schedule it creates

Thank you. I think I left most of the Advanced settings at default - but it’s very likely I might have misunderstood some of them. Here are screenshots of 3 of the zones. The rest look and act pretty similar to these. Any suggestions on what I should set differently?
(And yes, I do have extra zones and am happy to experiment with them)

Ok, so the first question is whether you are actually spraying out 1" of water per hour ?

So it could be that you are telling the system that you are putting down more water than you actually are, which would make the system water less often. Can you run a zone for 5 mins and measure the usage at your water meter ? This could be where you main problem lies.

So the formula for mm/hr flow rate will be Total Litres Flow / Minutes run / Area in m2 x 60: - that’s metric but you can convert it.

Could your root depth be too big ? I have 6" for warm season grass. With nearly 10", the system expects the moisture to exist down to 10", thereby further meaning that it will water less often since it expects the moisture to last longer at a deeper depth.

The co-efficient could be a bit light. I have 65% but I am deliberately agressively saving water but I think the 70% would be closer to the mark for really healthy grass.

I think that the default efficiency is 80% rather than 70%. I’m not sure of the effects in this but you could set this to 80% in a test zone.

Finally of course is the PWS. Is it pretty close to your house (if not your own) ? Is it at the same altitude as your house

Pretty much everything @championc said. I’d adjust the root depth to 6" max, and bump crop coefficient up a fair bit.

Confirm your nozzle inches per hour like stated above, or at bare minimum, find out your make and model, and look at the manufacturers spec sheets. That will get you a lot closer than a generic “spray head” in Rachio.

About when did you notice the lawn start turning yellowish-green? Bermuda and zoysia should start going dormant this time of year, and will appear a light brown/straw color through the winter into mid/late spring.
Both of these types of grass require about an inch of water a week, so without knowing the weekly rainfall breakdown, your monthly totals don’t indicate much of a shortfall that would need to be made up with irrigation.
Let’s start with the timing of the lawn color change and work from there…

Thanks very much. I noticed the Bermuda started turning brownish in early September and the Zoysia in October.

I couldn’t get to measuring the output yet (I’m currently away from home) but it looks like adjusting the root depth to 6” and crop coefficient to 80% helped bring the next watering days closer.

Thanks for the tip on 1” per week. I’ll measure and see if the Rachio is able to keep that up (not too optimistic since it has been 5 days since the last run, 3 days since last rain (0.4”), and the closest next run is 6 days away :thinking:

This is probably a very stupid question, but if it turns out the true output of the spray head is 1”/hr, would the goal be to get the Rachio to run that zone for 1hr/week to hit the 1”/week benchmark, assuming no rain?

Thanks again for all the comments.

Yes, if your sprays put out 1"/hr, then you’d want to calibrate your parameters so that it would run 1hr/week if there was no rain. It’s a little more complicated than that when using Flex Daily, as the system would run a little more frequently during times of high evapotranspiration (ET) when factors like wind, high temps, low humidity, etc… increase the rate of water consumption by your lawn.

Your lawn may have been going dormant due to normal seasonal changes in weather. Best to probably compare timing of when those sections go brown to your neighbors that have the same type of grass. Won’t have much to do until next spring in either case. Lawn should green back up in late spring when temperatures rise and we have longer sun exposure.