Question/Suggestion on drip irrigation control

Yeah, that 7.5 gal setup is on my list for the fall. I’d like to add additional 1/4" lines for the bigger plants. For that reason, I’d likely keep that at 1GPH. I know that @Modawg2k has a challenge with 2 GPH heads for the runoff reason that you mention.

I always start early-morning. Since I have a yard and garden that I want to have priority, my shrub zone sometimes has to wait until 6:30am or so. If it doesn’t have to wait it starts around 5am. I honestly don’t know if watering shrubs overnight would be a problem, other than at the start I’m guessing temps would be higher than they would at 5am, so you’d get more evaporation.

I rely heavily on the ‘Water Use It Wisely’ recommendations. It’s nice that we can use them to determine how many gallons to deliver. Just as useful is that once you have everything set up in Rachio on Flex Daily, you can also do sanity checks against the recommendations they give you for frequency of watering.

1 Like

Thanks for that. I’m thinking the most important rule for duration is to not produce runoff. Secondly, you wouldn’t want it too slow so that it evaporates before reaching the appropriate root depth…

There’s more to this than I imagined. And I came into this thinking an irrigation system would be no sweat - easier than having to water with a hose sprinkler; and certainly xeroscaping would be easier than having a lawn!

I’ll have a read, we’ll get this sorted out.

All true, but you’re going the harder path not just to get it to work, but instead getting it optimized. That way you don’t have to be messing with the controller between seasons, and you’re watering less than everyone else in your neighborhood! As you know, setting up fixed schedules that overwater is a piece of cake. :wink:

You have the right attitude and a lot of support on these forums, so it should be fairly straightforward for you.

1 Like

Xeriscaping. For drip a rule of thumb is it takes about 22 to 30 minutes to apply .25 inch of water. I would set a custom sprinkler up and call it drip. The pretend inches per hour would be about .25 inch per hour. Then put in your plant type, soil type, sun exposure. Try this and see if this about right.

Unless I’m reading you wrong, that doesn’t exactly take into account that on zone 1 I have 10 drips arising from my conduit: 6 that are 1gph, 2 that are 2gph, and 2 that are 0.5gph. Zone 2 is completely different with bubblers serving trees. How do each of those relate to 0.25in/hr?

For me it’s more intuitive to work through the math provided in David’s link above, I think.

@njhaley I forgot the link. Here it is:

First set you Area of Interest. Use your address, and draw a rectangle using the AOI icon. After that the link above will guide you.

I forgot to answer this. When you go through the Water Use It Wisely site it will give you a range of root depths for different vegetation types. You might need to use your judgement on where you lie in that range if you have varying levels of plant maturity and type. Keep in mind that setting deep roots tells the system to water longer and less frequently, so if you have less mature plants that might need more frequent watering you don’t necessarily want to pick the deepest estimated root depth in your zone.

Welcome to the forum, @njhaley. You’ll find a helpful bunch of desert rats here.:wink: Xeriscape and drip systems and the unique characteristics of our desert adapted plants can be a bit mind-boggling at first, but once you get the controller set up, you may be surprised. I appreciated your comment about seeing water being wasted pouring into the streets.

@azdavidr has done his homework and his posts regarding drip irrigation are absolutely worth the read. @Modawg2k turned his lawn from one with a dead spot to beautiful green.

Since your landscape is well established you may find it requires little water. Desert plants have several adaptations that help them during prolonged droughts. Some have waxy leaves, some have no leaves at all and some drop their leaves when there is little water available.

Lantana, hesperaloe (red yucca) and succulents such as cacti and agave have fairly shallow root systems, but they do spread out to capture rain water when it’s available. A saguaro’s root system is not often more than 4 inches deep, but spreads out about as far as the cactus is tall.

Over-watering these plants may kill them, so flexible daily schedules are perfect for this situation. My xeriscaped front yard is well established and I don’t think that my hesperaloe even has an emitter any more.

Now if those waskly wabbits would stop munching on it!

1 Like

It’s important to identify soil type.

There’s quite a bit of research being done on drip irrigation. Soil wetting patterns are affected by soil density and application rate–generally the denser the soil, the more the water spreads laterally.

Increasing the application rate (as in 2 gph emitters) will increase the soil wetting pattern laterally. The studies show that reduced flow rate increases wetted soil depth and decreases the wetted width.

1 Like

I’m in anthem and having these same issues but loving the rachio so far. Thanks for the links.

1 Like

Thanks for everyone’s help so far. The soil type is most likely sandy loam based on a Mason jar test, but it doesn’t go much deeper that a foot before I hit the hard stuff.

I managed to get everything installed this morning in less than an hour, didn’t even have to run to home depot for supplies to finish the install!

I did visit this afternoon to pick up replacement drip nozzles so I’d know exactly how much was being emitted at each plant. We also picked up a bunch of new ornamentals for the front yard which will be incorporated into the small plant zone.

I know I’ll be able to get this sorted out, but I still think there are some pretty significant problems with the way the software and app work today. I’m a pretty smart person, so I can’t be the only one that doesn’t get this.

For example: why can you only put one emitter per zone? I can’t be the only one who has these things stacked up in series - either in the desert or anywhere really. Without doing a bunch of non-intuitive math, it’s a pain for the layperson to sort out easily. Even for an advanced lawn care expert this is non-intuitive… Instead I think the algorithms are something only a soil scientist or a turf manager could digest - not your everyday homeowner.

This brings up the more important point I think: how can you be certain how much water you’re using and therefore saving? We’ve got almost a dozen drips in our front yard - some 2gph, most 1gph, some 0.5gph. How can the software ever take all of those into account and accurately determine how much water was used without knowing each and every drip connected in series on the zone?

Again, I love the system, it was a breeze to install and I’d recommend it to anyone, but I think these missing pieces are a serious flaw in the app/user interface. Hopefully it’s something they address in a future overhaul…

i set up a custom emitter nozzle myself for my drip then realized it thought it was pushing 200 gallons an hour. i’m in the same boat as you at this point.

What was your emitter PR and about how many emitters do you figure that you have ?

The software determines the watering time based on how much water is put out by the emitters, and what the needs of your vegetation are in your given climate and soil. Since there is only one valve controlling your zone, it can only use one emitter type per zone (valve) to determine your watering time. Note that the emitter is intended to be representative of all of the emitters on your zone. In my case, I have single 1 GPH emitters on my shrubs, so I set my nozzle according to that case. For my trees, I have three 2 GPH drips on each of them, so my custom nozzle is representative of a single 6 GPH emitter per tree.

I guess I don’t really see this as a limitation of the software, as much as it is of the irrigation system design. Going back to my example of shrubs, I’m currently not optimally watering each of my shrubs. I have small shrubs and larger ones. My larger shrubs might require two 1 GPH emitters, whereas my smallest might be OK with one 1 GPH emitter. I would still be OK with having one run time for the entire zone. Say that I set up my schedule to run 5 hours in this configuration. My small shrubs would get 5 gallons of water and my larger shrubs would get 10. The larger shrub should be getting more water so it’s all good. This puts the onus of having a proper irrigation setup on the consumer, but of course that’s already the case, regardless of whether you have a ‘smart’ or ‘dumb’ controller.

Let me know if this makes sense, or if I might have missed part of your point. Glad to hear that your install went well!


How were you scheduling your irrigation before?Just an observation: you have a mismatched zone with so many different gph outputs. If you must use these individual drippers, you should be using the same emitters throughout the zone. Are you connecting tubing directly from PVC pipe? I encourage replacing this type of microirrigation with drip tubing with inline, self-flushing, pressure compensating emitters.

Honestly I don’t know my system well enough yet. I’m still working on the grass. I can start a new thread for my issues just thought I’d chime in and say that grass seems a lot easier to configure than emitters.

That’s for sure! I hope you’ll find the post I reference above makes that process a bit easier. Since you live in the Phoenix metro area, you’ll benefit directly from the ‘Water Use It Wisely’ site that I reference in the emitter post. Let us know if you have any problems.

As @azdavidr has mentioned your concern is related to the zone itself, there really is nothing the controller can do to address a mismatch in watering needs on a single zone. I know the pain, one of my zones has all kinds of plant types with very different needs. There are ways to try to address this though. You should set your PR rate based on your most thirsty plants. The controller will then give you the run time needed for the plants. You can then use that run time to calculate the type of emitter you need for the rest of the plants by dividing the amount of gallons the plants need by the run time. Let’s take azdavid 's shrub example, for his larger shrubs he know he needs a run time of 5 hours with 2 gph emitters for his larger shrubs. For his smaller shrubs he only needs half the water so he chose 1 gph emitters and it works out. That’s what I plan on doing with my problematic zone once the heat let’s up


That’s essentially what I’ve done by paying attention to what’s in the zone - cacti are on a 0.5gph, shrubs and ground cover on a 1gph, trees and new addition shrubs on 2gph, the issue is how can the software adequately keep track of usage - it seems like it’ll run the same now and tell me “x gallons” vs. if I add one or two or three additional 1gph emitters. How can we get it to accurately calculate how much water is being used?

I mean, I know what it is because I can add up all of my emitters and I know how long the program runs, seems like that’d be an easy add on to the app. I think they’ll have to come up with a new way to approach this problem for all the users with xeriscaping and drip systems - many of which are in drought/intensive water management areas…

@njhaley I agree that getting accurate water usage from single-point emitter systems is cumbersome. You can back calculate an ‘Area’ value to plug into your zone that will be fairly accurate, but when you add more plants you’ll need to update that value. I agree it would be easier to just add a number of emitters for that. If you want to back calculate an area to give you a better reflection of your water usage for that drip zone, here’s what I did.

By the way, you may face other challenges with your current irrigation setup if I understand it correctly. Do you have cacti, shrubs, ground cover and trees all on the same zone ? The different emitter rates are nice for throttling the amount of water delivered per watering, but that range of vegetation also has a vastly different set of needs for frequency. For example, the cacti would be much better off with less frequent watering. They may eventually have problems if they are watered as frequently as your shrubs and/or ground cover.

1 Like