Fescue not getting enough water

I know fescue is a cool season grass but here over the last few weeks it has looked pretty bad and very dry pass 1 inch when I dig down into soil. I am in zone 7 using flex, clay loam, lots of sun, rotary nozzle on a flat surface. Set to 6in root depth. I have another location still with old fashion control (no wifi) set to a watering program and the fescue doesn’t look no where as bad. Help!!! What to do?

I was digging around looking at coefficients, and I found one that says the coefficient for most fescue is higher than the cool season grass default of .7 – I am changing mine today to .8 to see if having it water slightly more often will be better for the grass. You might also double check your soil type (and it’s AWC setting - @plainsane is VERY helpful with this), and also check your PR rate on your nozzles.

Link for the article on Grass Coefficients - http://irrigationtoolbox.com/ReferenceDocuments/TechnicalPapers/IA/2008/2127translated.pdf

How long have you been flexing? My opinion, and it may not coincide with others on the forum, is to take it slowly transitioning over to flex schedules, especially during the heat of summer. Unless you are very confident that you have the zone variables set accurately, or have the time and inclination to tweak them periodically until they are right, I recommend going to a fixed schedule with smart cycle and weather intelligence enabled. Also, pick a PWS (personal weather station) that is as close as possible to your location, Rachio won’t do it for you, at least it didn’t in my case. Then, just put in the minutes that you want each zone to run, and the Rachio will do it, as well as suspending irrigation if you get a significant cooling weather trend, or rainfall. Fixed schedules are kind of a dumbed down Rachio, but they still do save water and increase plant health if you enable weather intelligence. After you get through the heat of summer in there in Zone 7, you can experiment with your Zone variables to get the Flex schedules dialed in. Just my two pence

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yea, fescue will need insane amounts of water when you start punching past 90 as daily highs. here in ga. it is almost impossible to keep it looking good in august…you just cant through enough water.

Clay loam (.2inch AWC) takes awhile to deplete. I’ve changed my soil type to silty clay (.16 AWC) and my field capacity went from .6 inches (amount to fill bucket) to .48 inches. Net net, the soil gets depleted faster, and flex will water more frequently, with slightly less duration.

Colorado heated(?) up very quickly, I’ve moved my cool season grass to 85%. I’m now about every 3 days. If July is a scorcher, might have to move up even more.

This. This is probably the best advice I have seen on flex. I’m still learning my yard with flex, I think after this season I will have it nailed. Once the summer heats up, flex needs a little more TLC if you haven’t dialed everything in properly (at least here in Colorado).

Totally agree. Not as efficient as flex, but it works well and will save water/money with weather intelligence.

Can you join our customer support team? :wink: Love this rational, pragmatic advice.


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Ha , sounds fun. I bet customer support team is a smooth stress free commitment! As a residential irrigation contractor for the last 15 years, I’ve had my own challenges as “customer support team” for my many clients. Our climate here in Sunset Zone 7, USDA Zone 8 is extreme…wet, cloudy winters followed by 3-4 summer months of zero precip and many days in the low 100s. So far Rachio is solving several of my long time irrigation programming dilemmas. Plus, its allowing my clients to realize that, hey, your irrigation system is really inefficient and was installed without any design experience etc. Rachio is going a long ways to creating what I think will be a lasting legacy of water efficiency, less depleted reservoirs, and significantly less toxic run-off into our waterways here in the arid West. However, if the irrigation systems that Rachio is managing are inherently inefficient, then no software can deal with this. There are many more reasons why lawns go brown in the summer than just how much water they get. Is the soil fertile, compacted, grass cut too infrequently? Or maybe the home builder scraped off the top 8 inches of soil leaving you with scant topsoli before you hit bedrock? Water thirsty annuals planted amidst xeriscape drought tolerant landscape shrubs? Single drip emitters watering shrubs with ten foot canopies? These are the problems that I see on a daily basis. Problems that Rachio can not solve! However I do forsee that in ten years, Rachio, (or some other smart controller software-although so far as a contractor Rachio is by far the most resilient and promising platform) will receive some kind of environmental award for putting together the platform that was user friendly enough, but combined technologies adequate for those with sophisticated knowledge of residential irrigation, to save significant resources in the drought prone areas of the U.S. Looking forward to being part of the team!

I’m sure we could gain some valuable insight from you in regards to making the system more user friendly.

I usually call this garbage in, garbage out :wink:

Fully agree. There are so many variables.

We hope so. It’s going to be a fun ride seeing where technology takes us. Still waiting for low cost, durable, highly accurate soil sensors. If cars can drive themselves…


I agree. For years I relied on and recommended to my clients the cheap soil moisture sensors available at any hardware garden store. Problem is I realized, they are only accurate in clay soils per my experience. This makes sense given that clay soils have a much higher electrical potential than silty, loamy, or sandy soils and electric conductivity is what these devices measure. Case in point, here in my neck of the woods our predominant soil type is decomposed granite, basically eroded granite rock from fairly recent (25 million years old) geologic events. While our soil type is technically loam, decomposed granite has low electrical conductivity. If I saturate these soils and then test with a cheap soil moisture meter, it will often read zero. Happens all the time, even the more expensive soil moisture sensors ($75-100$) don’t seem to account for soil type electrical conductivity. There’s a reason why golf courses, large scale commercial irrigators etc have soil moisture meters that cost thousands of dollars!

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I did the same with mine a month ago. .8 works for most of my fescue though I had to put 2 of my zones at .83 and .85 for them to get enough water. It was night and day from the .7 setting I had it at previously. It’s still working great this past week as temps been around 105. Last year at this time my fixed schedule wouldn’t adapt during heat waves and I’d have to manually add more water.

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@GregS Thanks for sharing, warms my heart. At one point I was thinking of making the default crop coefficient higher for cool season grass but didn’t want to swing things too far in the other direction since flex monthly also uses that value.

I’m going to run some simulations and see if a default of 80% crop coefficient (with any new connected controllers) adversely affects other schedule types.


After reading this thread, I am increasing my crop coefficient selectively for my fescue zones based on visual observation over the last really hot days (clay, not much shade). The .7 had me do additional manual runs as well. This is great stuff, thanks for sharing.