Underwatering in Fall

I currently run a flex daily schedule. All of my settings are set at default. During the summer, my system would run for 3hrs and 14min 2 or 3 times a week (depending on temperature, rain, etc.). Now that we have shifted into fall, my system seems to be watering way too less. For instance, my system ran on 10/9. Since then, my Tempest has only registered .48" of rain. My next watering is not scheduled until 10/22. That’s a total of 13 days before watering. That doesn’t seem right. My grass has started to brown a little in spots and is not nearly as green as it was during the spring and summer. From what I’ve read and understand, my grass is supposed to receive 1.5" of rain a week. Since fall, I am nowhere near getting that much water on my grass.

Does something in the Rachio code change when progressing into the cooler seasons? Outside of totally deleting my schedule and re-adding or manually emptying my zone soil moisture table to kick off my schedule another time during the week, I’m not sure what other options to take.

This is your problem.

You need to dial in your settings for your yard in order for Rachio to work correctly. It will trail off in winter months and dramatically spread out the frequency of watering, but having all default settings isn’t helping you at all.

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I thought that’s what the dynamic setting for Crop Coefficient was for? Why would I need to manually make changes in the fall for my watering schedule? I thought that was the whole purpose of a “smart” sprinkler system?

You said all of your settings are default. Dynamic crop is only one of many settings thst could be “default” snd rarely one of the major issues…

By “default”, I mean all of the advanced settings have not been manually changed (depletion, efficiency, nozzle inches per hour, etc.) All other settings (spray heads, soil, zone type, etc.) have been dialed in to fit my specific yard. I’ve had these settings setup and working fine for the past two years now, so I’m not sure why this fall all of a sudden my system is only running once every 13 days after only receiving .48" of rain over that period.

The only factor that has changed in the last two years is the new integration with my Tempest weather station. Up until two months ago, I used a local weather station that was within .25 miles from my house.

@tmcgahey is correct in needing to dial in your yard in the flex daily mode.

That being said, the Rachio system tends to suffer in the winter and fringe months (at least in my area, Bay Area & cool season grass) primarily due to the fact that it only adjusts spacing in watering interval, not duration, ever. This works on paper, if all the variable are known, but in the real world, where there are tons of micro climates, ground water levels, variable root depths, etc… I find it best to manually intervein from about Nov to early March. I manually measure soil moisture once in a while in my lawn and trees using a 10" landscape spike. It takes about 60 seconds to poke like 10 areas to ensure that things are not dry and not saturated. YMMV.

I’ve had my settings dialed in for my yard for over 2 years now. It’s been just recently, once summer ended, that my system is now watering way more infrequently. I’m no where near getting 1.5" of water a week from my system as I was before. Like I said in a previous post, my system now runs every 10 to 13 days. I received less than .50" in the past week, so I would think that the smart system would realize that and move up my schedule instead of staying static.

I’ve recently added a Tempest weather station and integrated with my Rachio, but I don’t believe that is the issue. The only thing I can think of is that the system slows down the frequency of watering based off the cooler temperatures once summer ends. But doesn’t the system factor in temperature for the watering schedule? From what I’ve read and understand, you need 1.5" of water a week - that should include the fall and cooler months of the season (here in the midwest). I don’t know, maybe I am missing something here. Hopefully someone can shed some light.

Well, we don’t know anything about your yard other than you are running Flex Daily schedule, you have all default settings, and it isn’t working the way you want it to. You are correct in that Rachio will dial back the frequency as we head into winter months. The soil is not drying out as fast, and the plants aren’t sucking the soil dry as fast since ET isn’t as high in the winter months. My drip zones have drastically decreased the frequency now that we are not seeing 100+ temps here in Arizona, and come later into the season, I will go 2 weeks between watering on my trees. Unless you REALLY have bad settings, I struggle to believe that grass zones are stretching that far out.

At this point, we know nothing about your yard, what default settings you do have, what your moisture graphs look like, nothing. First step is going to be posting some screen shots of these things to see what is happening.

Here are some screenshots from two of my six zones. This first zone is my rotor head:

NOTE - Crop Coefficient is set to dynamic on my iPhone and it is showing as 74%. Not sure why it’s wrong here on the web.

NOTE - I emptied my moisture bucket earlier today so that my system will run tomorrow morning instead of two days later.

Here is the second zone that is a fixed spray head:

I have four other zones (one is a fixed and the other three are rotars) that are the same as above, so no reason to do any screenshots of those.

Let me know if there are any other shots you need and I will be sure to send them. I don’t see anything in here that is glaringly wrong or off that would cause 13 days between waterings.

Your crop ET for 10/16-10/20 is incredibly low, then your forecasted ET for the next 2 days looks “normal”. I haven’t had a chance to set up my Tempest unit, so I don’t know if there is a calibration or something to do with setup, but I’d put money that’s where your issue is. I doubt .04 ET is correct.

Otherwise, your default settings are probably not correct, but wouldn’t be causing the issue you are seeing here.

Outside of assigning your Tempest to your Rachio, there isn’t any calibration or setup outside of physically mounting and app setup for the weather station.

So what does the Crop ET represent? And how do I change that since there’s not a setting for it? By “default” settings not being correct, what are you referencing? Outside of doing a cup test to accurately determine your water output per zone, what else should not be set at default?

You can’t really change it. It is a function of weather (sunlight, temps, wind, humidity, etc.) and plant type as it represents soil evaporation and the water used by a crop for growth and cooling purposes.

I’m not really sure what would cause you to “observe” a .04 ET, then forecast a .16 the next day unless you’ve been having very gloomy, rainy, overcast days. That or there is an issue with your Tempest…

Not sure what is going on, but I realized that after emptying my soil moisture bucket yesterday in order for my system to run this morning, I noticed that my Tempest station was dropped and another station was added by default. After changing back to my Tempest yesterday, the crop ET went from .04, .03, .03 and then to .07 on the day I watered (today).

The next three days are showing .13, .15 and .16. I don’t know if Rachio dropping my station has anything to do with this, but it seems strange nonetheless.

I believe Rachio will automatically change stations if the station does not report any data for a period of time. I’m not sure if they do the same if the data looks way off as well.

From the outset it looked like prior or at 10/9 it should have watered… I believe the data was then @ .45 mute point now.
Look at nearby weather stations data, and compare.

@MichaelS76 It does look like your Rotor Nozzles @ 1 " inch per hour is probably incorrect check that… You would have to be pushing the highest pressure and the largest flow nozzle No.8 size to achieve that number.

Check your spray nozzles as well. Soil and Root depth. Unless I missed it you don’t say what your geographical location is but you certainly do not expect cool season grass to need 1.5 " of water in the winter months and should be a less percentage of that need.

I’m not for certain what nozzle number I am using for all of my rotors, but I did replace one this weekend and put in a #4. When it comes to the nozzle inches per hour, I was told by several people on here when I got started to just leave them at default if I didn’t do a cup test (1" for rotor and 1.5" for spray). So you are saying that I should lower both of those? I haven’t had any issues with the amount of water I’ve been receiving in the past. My issue has been just recently in the fall with the long breaks in between waterings.

I live in the Kansas City, MO area. I’m only planning on watering for the next month or so. I will shut down the system somewhere around the middle of Nov. I won’t be watering in the winter once we start getting really cold.

I believe my soil type to be correct as Loam. I left my root depth at default since I wasn’t exactly sure how to dial in.

Ok, well maybe the breaks between waterings are correct based off the season. Like you said, I shouldn’t be expecting to receive 1.5" of water in the fall - even though we are still seeing days occasionally in the 80s. Maybe everything here is functioning as it should. I don’t know.

Use the manufacturers product literature and specifications for your precipitation rate. That’s my initial suggestion period.

You should know what each and every nozzle you are using in your system and why.

You did a flow test and determined one of your Zones tested was @ .96 inch per hour. I’m guessing that’s in a spray zone of undetermined product manufacturer and nozzle type.

Living in KCMO area your soil is Clay not Loam.
However you being from there is making me hungry for some burnt ends and Gates BBQ sauce.

#4 Nozzle is at less than a half inch per hour (.48) and you can find that by simply looking it up.

Further, what I indicated was your turf plant does not require an inch and a half of water during the fall and winter. Has nothing to do with rainfall, or irrigation other than it’s a reduction of the plant water requirement.

You should always use professional irrigation products, Toro’s
T-5 rapid set is easy to use, tool less and has an extra inch of height, same as their 4" Pop up taller and better than competitors. Hunter PGP is a standard with a wide nozzle selection to achieve many results. Home stores carry other brands that look like , but do not perform the same.

Maybe this local link will help you.


I’ve replaced 3 heads in the past two years. I replaced them with Hunter PGP’s. According to their site, the precip rate for the rotors are .4. As for the others, I assume they are still the original or replaced prior to me moving into my home 5+ years ago.

I never did a flow test, so not sure where you are getting that from or the .96 inch/hour number.

According to websoilsurvey.com, the soil in my yard is the following. I don’t believe that to be Clay:

##### Typical profile

** Ap - 0 to 6 inches: silt loam*
** A - 6 to 13 inches: silt loam*
** Bt - 13 to 19 inches: silty clay loam*
** Btg - 19 to 56 inches: silty clay loam*
** BCg - 56 to 79 inches: silty clay loam*

And FYI - if you want the BEST burnt ends around here, check out Jack Stack.

I’m coming in to this late, but while 1.5" of water may be fine in the summer, it’s way too much now. Looking at the FRET value for Kansas City MO for this week, it is down to 0.55. Multiply that by your Crop Coefficient (let’s say 75%) and you should be needing about 0.41" of water per week, or 0.06" per day on average. Yes, it goes up and down, and Flex Daily schedules will account for that. Flex Monthly only uses historic data, and while it’s great to have your own weather station (local one near you or personal Tempest), to my knowledge, only the rainfall is used from your selected weather station. Temperature, humidity, sunlight, etc. are all using values for your area, I believe, not from your station.

As to the length of time watering, Flex Daily will pretty much ALWAYS water the same amount of time, just less frequently, while Flex Monthly varies both (one of the things I like about Flex Monthly). I use Flex Daily, but reduce my Allowed Depletion in fall to have it water less at a time but more often; you could consider that.

As to grass turning brown, you obviously know what happens to your grass in the fall. Back up in Pennsylvania, our grass would stay green all year, even under the snow. Here in South Carolina, it turns brown/tan in the winter, and is starting to now a bit. Possibly some of the color change is normal, but you know more about that where you live.

BTW, you can check the FRET value for your area at https://digital.weather.gov/. Under National Digital Forecast Database Display map, click the dropdown that has Maximum Temperature at the top, and go to the bottom and select Total Weekly FRET, in, which is the amount of water required for a crop with a Crop Coefficient of 1.00. Find your area on the map, and read the value, multiply it by your Crop Coefficient, and you should have a close value for what your crops/grass need for the week.

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This is great information. Thank you for sending. I didn’t realize that the need for water in my lawn would drop so significant from summer to fall. It would appear that my system is truly running correct based off the need of water for the current season for my fescue grass.