Engineering team hard at work on v3!

Except I don’t believe the Iro2’s calculation for ‘Crop Evapotranspiration (-)’ is affected by temperature or crop season. Hopefully enhancements to arrive with Iro3.

Best regards,


@a0128958, our scheduling inputs are the same for both Gen1s and Gen2s. The calculation does account for temperature. The crop season is currently static and can be edited within the advanced zone settings menu. If your Flex Daily schedule was created before May 2016, the crop coefficient dynamically changes on a month to month basis.

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It was hard for me to see less watering in cold months than in hot months, all else being the same (wind, humidity, insolation, rain). I’ll keep looking for the affect of lower temp / less water - all else the same.

If in full automatic mode, which is focused on maintaining soil saturation at or above 50% (for example) by zone, it would seem that you’d have to put down the same amount of water in November than in July, all else the same (wind, humidity, insolation, rain). It surprises me that you’re saying that the calculation of ‘Crop Evapotranspirationn (-)’ is adjusted by ambient temperature.

Best regards,


@a0128958, thanks for confirming. I reviewed your account and I’m seeing a decrease in water usage during the winter months – here’s a screenshot of your water use month over month for 2016 (July is the peak watering month @ 29K gallons):

If you haven’t already, check out this support article to see how you can download the data we use to create these graphs.

Let me know if I’m misunderstanding your question. As I’m sure you already know, the watering durations don’t change on Flex Daily schedules, only the watering interval on a zone by zone basis. Also, we don’t currently record any “savings” with Flex Daily schedules since the watering events are not skipped, but simply delayed and rescheduled to supplement mother nature.


I understand most of this. Thank you.

I wasn’t seeing very aggressive watering reduction as the winter months arrived, due mostly I believed to ambient temperature and crop growing season parameters not being used for Iro2’s calculation for ‘Crop Evapotranspiration (-)’ (while being mindful of how other factors, such as rainfall, can substantially influence the subject).

Your chart (thank you) shows this, with the exception of the last month. In this case, I just gave up, put the controller into manual mode, where it has remained for a while. It’s also why I stopped posting the monthly summary commentaries.

IMO, given the update here, your algorithm for computing daily adjustments to ‘Crop Evapotranspiration (-)’ is not as aggressive as it could be toward putting down the least amount of water in a fully automated manner in winter months for the Dallas climate.

Parks and commercial entities are thus going to use more water in Winter months than they need to with your product. IMO.

Best regards,


I am experiencing the same issue. I had to manually fill all my zones because during the colder days in January when the grass was still dormant my sprinkler system was still going off at least twice a week in Central Texas. Before I knew it I saturated my lawn and turned my neighbors into a marsh all while trying to water dormant grass in completely saturated soil. This goes against the ease of use that the Iro is marketed. It seems I spend more time fiddling with my Iro2 than my old manual system.

I also was experiencing watering and over-saturation here in San Jose CA when we are experiencing 100 year rain cycle. Some more aggressive adjustments clearly need to be done on the slope of the ET equations. During normal years I rarely water between mid November and mid February at all and this year is many times that wet. I eventually turned the unit off (standby). One issue seems to be the lack of duration variation throughout the year for flex daily during the year. if that had a 20:1 variation, the system might not panic that the ET rate would go under a threshold so easily. Just a thought.

Another V3 winter/rain thought that could use some improvement is the need for a new variable for rain effectiveness which mainly effects discrete dripper setups. When it rains a larger ratio of the ground is wetted than during an irrigation event. Perhaps 2x multiplier. Lawn sprinklers would be largely unaffected by this ratio (100%), as the rain area equals the irrigation area (although the uniformity would be higher 100% vs 70% or so for normal sprinklers, so this could help with that adjustment)…

Interesting ideas. I’m trying to visualize this through software. My fear (which is mostly realized) is when we have normal or less than normal years without this amount of significant rainfall.

Thoughts on a better way to track super saturation but not let it water too little? There are a lot of dynamics that we try to track, but I agree probably a better way to track massive amounts of rain.


@franz I will continue to think about this complex adjustment topic. My first thoughts are around a non-linear affect to water/root depth. If there is a ton of water 24 inches down, it does not necessarily mean that there is water in the first 4 inches if the sun pops out for shallow roots, but almost for sure the ground 8 inches down and further will always be close to saturation, likely above maximum desired. A few hours after adding an inch of water will have no affect on the soil below 8 inches unless it is sand down further than a few feet. Saturated is saturated. Supersaturation would seem to have a depth, like the depth of the cleche layer in some soils. Until conditions cause that layer to dry, there will likely be a range of wetness above it (non-linear). Sometimes going manual for a while is 100x easier than trying to automate it.

@a0128958, We agree – dynamic crop coefficients would help with seasonal demands on watering.

@bugs30, I reviewed your zone settings and it appears your root zone depths are currently set to 4" – we recommend a 9" root zone depth for warm season grasses. Changing your root zones to the 9" target would more than double to intervals between waterings.

@bug99, Flex Daily schedules are designed to manage soil moisture balance, as such, the duration should not change since your “water tank” does not change in size from season to season.

One of the difficulties in working with rainfall is estimating the fraction of total rainfall that is actually stored in the root zone; this is know as effective rainfall in the irrigation world. Small amounts of rain water usually do not reach the soil because it it held in the mulch or thatch. Some rain water mat percolate below the root zone and become unavailable. Additionally, depending on the intensity and duration of the rainfall event, runoff can occur and not be effective.

We’re exploring new saturation limits to help address this issue.

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I totally agree. When teasing out solutions, i recommend keeping a least these two items in mind.

  1. super saturated soil brings water up from below the root zone through capillary action. This is the hard nut to crack without extra data from a sensor or service.
  2. small to medium amounts of rain in the non-wet season will wet 100% of the soil in the first inch (assuming no runoff), vs drip which is a much smaller fraction, growing in a cone shaped by the soil type to some depth. If all of the roots are in the wetted cone, the areas / efficiency are about the same. This might be the case for a mature plant with deep roots. This issue is not as hard to solve, but is also less important, especially for grass zones.

I am not convinced that this is true. If we treat the sub root zone moisture and the moisture that is outside of the cones of the drip system as a second tank feeding the primary tank, the size of the tank effectively increases during the wet season. Perhaps knowing something about this from the weather service will allow the tank size to slowly vary to help fix this super saturation issue. Thoughts?

@bugs30, I reviewed your zone settings and it appears your root zone depths are currently set to 4" – we recommend a 9" root zone depth for warm season grasses. Changing your root zones to the 9" target would more than double to intervals between waterings.

@emil If I did that I would set my root depth far deeper than my roots which are currently at 5-6" as measured. This grass was sodded two years ago. I already have problems with the grass being too dry during the summer and this would make it worse. That’s the issue. It’s too dry during the summer and too wet during the winter when the grass doesn’t grow.

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Wouldn’t supporting soil moisture sensors be a better way to support this? Instead of estimating get the actual moisture. Quite possibly even get the moisture at different levels for a complete picture of saturation. Some sensors even work as a mesh so distance from the Iro wouldn’t matter as they would pass the signal from one to another. This seems a lot simpler and far more accurate method.

I need 24 zones to get rid of my 1982 style Hunter iCore… please!

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I just purchased a Gen 2. In case you guys get apple to work with you with HomeKit, will I need a new version or would the hardware of Gen 2 work well with it?


Until Apple has an irrigation profile for Siri I can’t comment on HomeKit support.



I just want rachio to be simpler.

I don’t want to tell it all about my soil, size of the zones, etc.

I know how much runtime each of my zones needs to run to deliver 1" of rainfall.

I want to tell rachio exactly that, and I want it to run the zone for less time accounting for recent rainfall amounts.

If zone 1 needs 3.5 hours of runtime to reach 1" of precipitation, I know that the zone delivers roughly .285" of water per hour. If it rained .35" yesterday, I know I need 2.28 hours of runtime instead of 3.5.

My goal is always to apply the 1" of rainfall as close to one duration as possible.

When I build the schedule, I’ll tell it “the ground is dry”. rachio knows I need 1" of rain in a single duration per zone, per week. Look at the forecast - if rain is forecasted for Thursday, don’t wanter on Monday. Wait until Thursday, if no rain, then go ahead and irrigate.

Maybe some of the current schedules are capable in some regards, but it just is too much work to setup, and never seems to do what I am looking for.

There needs to be simpler integration with a rain gauge or personal weather station, and or soil moisture sensors. My closest weather station even at 10 miles away receives completely different and irrelevant precipitation amounts compared to my house.

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I installed my Gen2 unit today. Some things I’d like to see are…

  • Well pump delay between zones
  • Manual buttons exposed without removing the cover. I’m tempted to cut my cover to expose the buttons so the family can easily kill the sprinklers if the need arises without fumbling with the latch on the bottom or having to go grab a phone.
  • Hinged cover, not the flimsy current one that you can easily drop when it pops off.
  • Move the latch placement for the cover. Right now it is up against the wire entry area and with larger wire bundles behind the latch it can be tricky to sneak your finger onto the back of the latch.
  • Easier to read zone #s around the LED indicators
  • A way to plug in a non-smartphone remote, like the Hunter remote control for irrigation companies to plug into quickly when opening/closing the system in spring and fall. No, limited access is not what I want here. I want something quick, dirty, and simple they can use.
  • Z-Wave+ integration
  • Wi-Fi signal indicator (maybe re-use your 1st-4th LEDs for a special mode that shows signal strength.
  • Accessible via Smartphone without Rachio cloud systems for control if Internet is down for a bit.
  • Same as mwahlert, an easy way to say “I’d like # inches of water per week”
  • Weather Underground integration
  • No use for me, but the ability to daisy chain two or more of these units together and treat them as one logical unit for customers with >16 zones seems like a logical thing to do.
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  • Ability to define a fallback/secondary weather station in the event a WS is offline for an extended period of time.

I just want it to be simpler. I should never be directed to read an article on a university website before watering my lawn. (eg, crop co-efficient)