Underwatering in Fall

post by MichaelS76 on Oct 17, 2022

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.

post by tmcgahey on Oct 17, 2022

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.

post by MichaelS76 on Oct 17, 2022

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?

post by tmcgahey on Oct 17, 2022

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

post by MichaelS76 on Oct 18, 2022

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.

post by bug99 on Oct 20, 2022

@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 intervene 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.

post by MichaelS76 on Oct 20, 2022

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 not 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.

post by tmcgahey on Oct 20, 2022

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.

post by MichaelS76 on Oct 20, 2022

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.

post by tmcgahey on Oct 20, 2022

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.

post by MichaelS76 on Oct 20, 2022

Not sure what is going on, but I realized that after emptying my soil moisture bucket yesterday, 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).

post by tmcgahey on Oct 21, 2022

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.

post by MichaelS76 on Oct 21, 2022

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.

post by tmcgahey on Oct 21, 2022

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.

post by ProWater on Oct 23, 2022

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.

post by MichaelS76 on Oct 24, 2022

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.

post by ProWater on Oct 24, 2022

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

post by MichaelS76 on Oct 25, 2022

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.

post by rraisley on Oct 30, 2022

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.

post by MichaelS76 on Nov 1, 2022

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.