Phoenix AZ Use Suggestions?

New to the product, and I live in Phoenix. I hunted around the forums but haven’t seen anything on accounting for the peculiarities of living in the desert.

I just installed my Iro and set it for Flex. Soil type clay and trees/shrubs/summer grass in my zones. The actual plants are all desert flora, so “shrubs” are things like a Mexican bird of paradise.

Can anyone let me know if I need to make any adjustments to account for desert plants? Or will the flex schedule get me close to where I need to be? I’d rather avoid manual schedules since that’s sort of what I bought this for. I assume there are others in the area who have tuned theirs for the best results, so trying to see if you can share.

Or, if anyone at Rachio knows.

Because if I kill the plants with this thing, I will be in a wee bit of serious trouble :slight_smile:

@crashtkd, welcome to the community! We hope you’re enjoying your Iro :smile:

I’m not sure if you’ve seen this thread yet, but @sunny recommended this resource to us. It’s written for the Arizona desert and has some worksheets to help determine run times, a picture to help estimate emitter flow, and an explanation of how to perform a catch cup/can test to measure sprinkler output.

The biggest variables you’ll need to figure out for your system are:

  1. Root Zone Depth (this will vary based upon the plants you have on a zone by zone basis)
  2. Nozzle output; AKA precipitation rate (this will vary based upon the emitters you have on a zone by zone basis). To create a custom nozzle, please refer to this support article.

Flex schedules will automate what you’re hoping to do, but they are only as good as the data entered into them. For details on all of the data points Flex schedules keep track of, please refer to this support article.

I hope this helps. Let me know if you have any further questions.

Best, Emil

Great, thanks, I think that’s most of what I need. One question- when figuring out the nozzle output, do I need to add up the total number of emitters for the zone? Or just per-plant (e.g. if I average 2 per shrub I add them together), or single emitter flow?

Yep, I’m new to all this.

Then, do I need to adjust the area or anything so the total gallons used is accurate?


I live in Tempe, and have been using the controller for a while. I tried the flex schedule and eventually gave up on it and went to the fixed schedule, but will probably give it another try later. My main advice if you are trying the flex schedule is to watch your plants for signs of stress. I found that it seemed to think the plants had more water than they seemed to by observation (at least when I tried it during the summer). I also used some Desert Botanical Garden info and also from Arizona Municipal Water users. These resources suggest how often you should be watering certain types of plants in the Phx area and I could never get the flex schedule to come very close to replicating that.

There is a feature in the station section where you can see moisture levels (at least as Rachio thinks they are) and then adjust them to full or empty. You will need to make sure the system is zeroed out either way (full just after watering or empty just before) so you have the right starting point if you want flex to work.

Theoretically this should be great for the desert, so I haven’t given up. Just watch your plants. Also please post your experiences because if you find it working great I would love to hear how you approached it.

Yeah, it definitely isn’t working well. My plants are all showing signs of stress, although the overall schedule looks close enough I hope I can get the variables fine tuned.

Thanks for the tip on adjusting the moisture levels… I’ll try that next. I also just upped the fine tuning for more water, and am playing with other variables to get the frequency a bit higher. I think if Rachio added a frequency tune like they have the amount tune, that would get it back on track.

100% agree. This is in our roadmap, will get to it as soon as we can. I’ve heard this feedback that people really want to use flex but it’s too hard to tweak right now. This feature will get in, just don’t know exactly when yet.


@crashtkd, I think we might want to double check your nozzle settings. When you’re ready to give Flex schedules another try, let us know and we can fine tune your zone settings.

Sorry I didn’t see this question sooner. When calculating your nozzle output (precipitation rate, or “PR”), you’ll need to factor ALL heads/emitters. Here’s the equation:

PR = (96.25(A*B))/©

96.25 = constant that converts gallons per minute (GPM) to inches per hour. It is derived from 60 minutes per hour divided by 7.48 gallons per cubic foot. times 12 inches per foot.
A = #heads -or- #emitters
B = flow rate (GPM) per head -or- emitter
C = zone square footage

Yep, see variable “C” above.

@garmanmd, just curious, did you review your nozzle settings to ensure they match the PR on a per zone basis?

Could you post these recommendations here for us (and other users) to review? I’m curious what scheduling interval they are recommending.

Thanks for your support and willingness to test and provide feedback on Flex schedules.

1 Like