Phoenix AZ: Need help adjusting schedule

Installed my Rachio back in October and have it connected to the local weather station and working great. Well, until the brutal AZ summer started to kick in. Now, most of my plants are drying out and I’m manually adding additional irrigation cycles or watering from a hose.

I’m guessing that there is an easy way to modify my settings to adjust for the summer heat? Anyone out there able to guide me in this endeavor? Tooling around I see that I can keep my current flex daily cycle but simply change the two sections with poor results (my shrubs) to 150%. Is that acceptable? Suggestions?

BTW–my soil was setup as this: Sandy Loam ‘Available Water’ (AW) to 0.08.


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There are a lot of Flex power users from the Phoenix area on this forum @jeremysm1, so I’m sure we can help get you dialed in better. First of all, where did you get the AW of 0.08? I’m not sure that’s the issue, but it’s a good starting point. If you could also post screen shots of the zones that you have in question, including ‘advanced settings’, we can get going.

And regarding your shrubs, if you haven’t already done so, take a look at this post and report back how close you think you have been to the associated recommendations.

Attached is a screenshot for my backyard Rachio setup–the front yard has a different zone but same setup (same vegetation). Also have a trees zone. TBH, I don’t recall how I came up with these settings, but when I installed the system several people guided me. In addition, I’m sure the square footage is incorrect. Let me know your thoughts. Thanks!

@jeremysm1, the best advice I have to offer would just be a repeat of the two posts below. I recommend you go through the soil survey first, then the drip link which I pointed to previously. Your Available Water, crop coefficient and root depth all strike me as being too low. Please post back after looking through both of these threads and let us know what you find. You may need to take incremental steps to get to the point where you are watering according to the recommendations below.

For reference, here are my settings. There will be variability based on your plant type and maturity. If you’re seeing issues with wilting, etc, then I’d venture to guess you need to bump up your root depth and crop coefficient. The root depth will create deeper watering, but will also drop back the frequency. The higher crop coefficient will create more frequent watering. Still be sure to double check that Available Water setting before making any changes.

From the websoil survey site, here are my screenshots with the info we need: (I used 40 inches deep for this example)

Also, if I put a bottom depth of 30 inches or less, the Rating (centimeter to centimeter) is .09 instead of .08.

It looks like you’re about right for a starting point. Maybe bump up to .09 or 0.1. Some have said that when their neighborhoods were built builders bright in a lot of to soil which may make the numbers different, perhaps more like loam? If it were me I’d bump the AW up just a tad then consider your vegetation. If you have plants that aren’t too water hungry the 0.5 for crop coefficient would be ok, but if you’re like me something closer to 0.7 might be in order. Once you make that adjustment move on to the drip calculator link.

I’m thinking a quick Arizona poll might be interesting and helpful. @tmcgahey, @Modawg2k, @sunny and @JPedrego, what do you use for your shrub crop coeficientes? I have some boxwoods that get sad if I go too far below 0.7.

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@jeremysm1 Your numbers look pretty close to mine, with the exception that I’m at .09 on the AW. My big question for you: Are you using the default emitter nozzle that in on the Rachio? Or did you create a custom nozzle?

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@Modawg2k, would you say that most of your shrubs are fairly drought tolerant? If it weren’t for about 2 types I have in my yard, I’d be able to drop lower. Last year when the temps cranked up they weren’t happy. 0.7 seemed to do it.

I’m using an emitter called “Emitter” and believe it’s the standard one. Almost all of my vegetation is the form of shrubs or similar. I believe they either have .5gph or 1gph emitters on them. Do you guys have a recommendation for the emitter size I should use on these, and also should I setup a new emitter reflecting that size? I’m going to change my settings to the .09 AW and .7 CC for my front and back zones (shrub zones). Going to look now at the next link you sent. Thx

Some are, but some aren’t. Those orange jubilees that I posted about are supposed to do well but they always look in pain, so that’s where I’m focusing my emitter changing first

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That sounds like a good plan @jeremysm1 . The higher the crop coefficient number, the more frequent the watering. If your yard gets ‘happy’ again you can experiment with gradually dropping down from 0.7. With regards to the emitter setup, that drip calculator you’re moving on to will walk you through it. It will help you to make sure that at each watering event you’re supplying the recommended amount of water.

Thanks! I’ll need to dig into that spreadsheet a bit deeper, but I have adjusted the other settings and we’ll report progress. I’ll probably have some more questions after I have time to digest the spreadsheet (later today).

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I have 2 GPH on all plants and I can tell you that the default Emitter nozzle was not watering long enough and my plant were suffering. It only makes sense that since your settings are like mine, that yours were hurting a bit too

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I’m sure that my plants around the yard are mostly 1gph–some of the desert/small plants could even be .5gph bubblers! The trees I believe are 2gph. Looking at the chart, I have no clue of what I should be targeting for the “Gallons you want to apply to each plant in one watering cycle” section. In the example, it shows 7.5 gallons and for the section “Inches of Water applied in Flex Daily schedule” it shows 1.19.

In my Flex Schedule for the back-yard, it shows .60! I made the changes as mentioned in the prior posts, and also changed the back-yard and front-yard to 130% as of now–just to get more water now before plants start dying.

Did you read through all of the spreadsheet instructions @jeremysm1? It walks you through using the ‘Water Use It Wisely’ information which will tell you how many gallons you should target.

Just FYI, in my yard I have mostly 1/2gph emitters and I use a custom nozzle of .2in/hour. You definitely want to switch from the default.

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I have 1gph emitters on all my shrubs, with the biggest of shrubs have 2 1gph emitters. Right now my CC is set at .5 and everything looks pretty good, with the exception of a few shrubs that always suffer this time of year (high temps and no humidity). These shrubs include hibiscus and silver bush morning glory, but once the monsoons hit, they spring back and look amazing. I’ve thought about messing with bigger emitters or something, but in reality, there is 2-3 weeks a year where they don’t look their best, so I may just leave it. I think if you have a problem with only a couple plants, I would address the emitters on those specific plants rather than adjusting the whole system, which seems to be working well…

Oddly enough @azdavidr, my boxwoods are doing great. Bigger and fuller than they have ever been! The rest of my yard consists of about every plant known to man, some drought tolerant, some not…I’ve got Little Johns, Lantana, Asparagus Fern, Foxtail Fern, Green Carpet, Chihuahuan Sage, Deer Grass, Dwarf Myrtle, Twisted Myrtle, Green Cloud Sage, and Bougainvillea, just to name a few. :joy:

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