So Cal, St Augustine, Flex daily issues

I have been a Rachio user for years, Gen 1 now Gen 3. I have St Augustine grass in Loam and full sun. Landscape Architect, Maintenance Co., Landscape Contractor all believe that my controller is the issue (or maybe the way “I” set it up is the issue). Watering had been short runs (approx 9 min per station) on a flex monthly that was watering every day of the week (FYI, 100d today). Suggestion was to increase my root depth by watering longer and less often. Called support and worked on a flex daily schedule with the soak cycle. Ran last eve just fine but notice that the next watering is 4 or 5 days out (I also reset zones to default). I don’t think my lawn will do well with 4 to 5 days out. Trust it or what would the recommended settings (advanced) be for St Augustine? I’ve tried tweaking root depth, efficiency, etc but it is a maze/puzzle that maybe solves the frequency but then goes back to short cycles. Should I just use the manual mode?

Especially since you’ve been changing many of the variables, we’d need screen shots of your zone(s)'s variables including Advanced variables, and maybe a look at the moisture table to see what is planned.

Interested to know what you find as also in SoCal with St. Augustine and need to make adjustments. For what it is worth, I have my Gen 2 set to water the 3 days available in my area (local restrictions) and it appears to be overwatering. Mine currently runs 21min on Tues, 11min on Thurs, and 21min on Sat.

My daughter has St. Augustine grass in Austin, Texas and uses a Flex Daily schedule with no restrictions. Her root depth is set at 5". However, her soil type is clay. Loam would probably need a little more water. In her sunny zones she puts down .45" about every 4 days right now, and her grass looks fantastic. Austin is also very hot. High 90’s every day.


I’ve attached screen shots for review. All zones are set up the same. Lawn was aerated and fed two weeks ago. Working with Rachio support we emptied the zones so that we could see a baseline. I also deleted the schedule and created a new one. Thanks in advance for your help.

Linn, thanks!

Your Advanced screen looks okay. 0.95 Crop Coefficient seems a little high, but I’m not as familiar with St. Augustine. Other values seem good.

I’m assuming you’ve changed some things in the last few days, as a 0.16" change in moisture balance increased the % by 51% on 8/27 or 3.19% per 0.01", a 0.5" change resulted in 97% increase or 1.94% per 0.01" and a 0.33" change increased % by 65% or 1.97% per 0.01". So looks like something got changed about the zone about 8/28. And I assume you watered manually on 8/29 for the 0.77" or Rachio was catching up. But the 0.51" planned for 9/1 is correct per your variables, so think you should be okay there. Also, based on your average ET (Crop Evapotranspiration) for the week of 0.19 (1.32 total divided by 7), the 0.51" of water should be applied about 2.6 times per week (every 2-3 days) which sounds right for hot weather.

That sounds good. The only other concern would be the Nozzle Inches per Hour. For the Rotary Nozzle you’ve selected, Rachio defaults to 0.7" of water per hour, while you have 1.5" per hour. My experience is actual nozzle flow is often lower than Rachio’s defaults, meaning it could be lower than 0.7". Where did you get 1.5" per hour? Using that flow would result in half the time and water being applied that Rachio would recommend. You may want to consider measuring actual flow by using Catch Cups or measuring Water Flow & Area.

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My daughter’s Crop Coefficient is set at 65%!

Thanks for the feedback. I think you helped me with what I need to do next. Too many variables and Rachio doesn’t look at some of “health” issues not related to water (compacted soil, pests, etc). The other issue is I don’t want to get my PhD in “lawn”.

What do your think of this approach for the grass: Switch to a manual mode watering 30min per station every third day until the lawn looks good. Decrease times until I find the low (watering times) then switch to “monthly” and tweak the settings to match the times I found in manual mode.


Linn, I had changed to .95 in order to get to the times I thought needed ie: I wanted the lawn to be watered longer/less frequent in order to get the roots to grow deeper. Rachio is kind of a maze…or maybe it isn’t meant for St Augustine:)

A higher Crop Coefficient will water more often, but it will NOT water more/longer at one time so won’t make the roots grow deeper.

I’d prefer you adjusting Flex Daily correctly (which it looks to me like you’ve done) and let it take over. Then adjust the Crop Coefficient up or down if the lawn is too dry or wet. Flex Daily takes into account actual rainfall and changes in weather, while a constant 30 minutes every 3rd day does not. As I mentioned above, I’d expect Rachio to water with your current settings about 2.6 times per week, so you’re close.

Any thoughts about my Nozzle Flow concerns?

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Richard, Not certain about actual nozzle flow… I reset to default and will see what happens.
Linn, same as above for the crop coefficient.

I’ll look to see if starts to head south and make adjustments.

Thanks to both!

I think your nozzle flow is way too high, if you actually have rotor nozzles like the Hunter MP Rotators or Rainbird or K-Rain equivalents. The Rainbird I believe are the highest PR of the rotor nozzles at .7"/hr, where the Hunters can be .50"/hr or less. If this is the case, you could be putting down a half to one third the amount of water you need to…

I just run my Rachio 3 on manual, tweaking the watering time of seven zones, by the color of the grass. The front of my house faces east and gets a lot more sun than the back, as there are woods in back of my yard that blocks the sun. For that reason, I set the watering times twice as long in the front as in the back. I also installed larger spray nozzles in some of my Rainbird 5000 popups to balance the zones more evenly. They all came with a #2 nozzle, but some do a full 360 where others only do a 90, so the longer sweeps need a larger nozzle to even out the spray volume.

,8 to ,85 crop coefficient for that grass is what I use in so cal. It can’t tolerate higher. I use flex daily with a two day only water restriction.

Thanks to all. I reduced the nozzle flow to .6 and tweaked the Crop Coefficiency To .8.
It’s looking better and I’ll contribute some of the problem to: Extreme heat, compacted soil and general poor lawn health. Feeding, aerating has helped a lot.

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Does that work out well for you? Flex really doesn’t usually work well with heavy watering restrictions.

I’ve been in a three day restriction for years and they recently went to two here in so cal. Three worked fine. It’s been really hot so tough to assess the two day but things are hanging in there.

The other smart controllers i have also have a drought zone setting so in addition to the day restrictions there’s some sort of overall setting that i can adjust.

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