Dynamic Crop Coefficient

Anyone appreciating the dynamic crop coefficient feature? I’ve always been manually changing it myself when the seasons changed.

In Houston Texas and it jacked up my St. Aug crop coefficient to 86%. Sounds pretty high! We’ll see how this goes. Tried to offset it by increasing allowed depletion up to 70%.

I see this post from @drew_thayer (Crop Coefficients and Plant Type - #10 by drew_thayer) where he posts a link to Chapter 6 - ETc - Single crop coefficient (Kc) but the only table that lists a warm season coefficient is for subhumid climates. Would a subtropical humid climate change these coefficients or has the rachio software already accounted for this? Been having some large patch issues in the past and don’t want to overwater my lawn.

Is there more info about this new feature or are we in the guinea pig stage?

Personally, the documentation on how to use it and what it does, is pretty poor.
Seeing no benefit of using this at all here in the midwest (Wisconsin). Wish they would add more meaningful updates (like fixing the watering time before sunrise, and not having it water at midnight).

So no, not really appreciating it.

More info like a table of values would be nice. Though at the moment it has my stone fruit trees at 46% which is about right for April. Come May it better shoot up to 85% or so. I’m keeping my citrus off dynamic since their ETc really stays essentially the same most of the year. I wish they had a way to specify evergreen or deciduous trees at least.

Keep an eye on it!

Obviously, the dynamic crop coefficient is of extreme interest to me. And while I am also interested in the workings of it (engineer, after all), I’d like to know where it is.

I have an Android phone, and don’t see it there, nor on the Web version. Is this only available for iOS?

It is in all platforms. Under crop coefficients you can choose to manually set, or lock it in and let Rachio adjust. The question in the other thread is how exactly it is going to work, and if it is regional or what.

Thanks, it is there on the Android, but not on the web version, which does report the changed dynamic setting, but also allows you to change it. I usually use the web interface, being larger with more information and as I’m always at the computer.

Oh, wow, while the one zone 1 I set explicitly to Dynamic did update on the web (from the default of 65% to 80%), the other zones on the web remained at the 65%, even though from the phone I specified to apply dynamic to All zones. That’s going to be a bit of a hassle until they update the web version. For that matter, which is used to actually operate the system when they differ like this?

I’m just now seeing this feature on my iPhone. Was this included in an update? Mine was setting locked at 80%. I just set to dynamic and it lowered it to 64% which raised my soil moisture by 11%. I guess I will leave it as dynamic.

I updated my iPhone app and then saw the option to switch to Dynamic. I switched all zones at that time. But this option is not showing in the browser interface (Chrome). Still shows the old static settings…

It is live!


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Why does this chart show 1.04 in April for cool season grasses, when peak summer is only .94?

***ohh this is just for California…

This is in the dynamic crop FAQ


That is when the grass is growing the fastest, growing the most, and going to seed, thus needing more water. All of this requires more water relative to other times when the grass is growing slower.

Is the dynamic crop coefficient intended for very high quality turf or just average home lawns? I’m interested in whether I can dial it back a bit if I’m okay with an average-looking lawn? (I understand that any dialing back would be manual, I’m not discussing an automatic offset here.)


@Gerardv514 I’ve always wondered the same thing for the warm season column.

@ECOBEARD If that’s the case then you would expect the crop coefficient to be higher for the warm season grasses during the summer when the grass is growing the fastest, however, the (2) highest crop coefficients on that chart are in March and May with April being lower than both and then July/August being lower than all three of those months. Wondering if it has to do with the root development being higher for those periods even though there’s not much top growth but I can’t find anything to support that.

My dynamic crop coefficient for my St. Augustine grass in Houston this month is 85%. Seems kind of high but I increased my allowed depletion to 85% to see if I can find a good middle point.

My crop coefficient just increased to 98% this month. Seems like a lot! Trying to offset by bumping up allowed depletion to 85%. Might just go back to non dynamic.

A bug with applying the correct figure for Dynamic Crop Coefficient has been identified and fixed. If you have set it, it may be worth re-setting it back to manual again and then back to Dynamic


My Warm Season grass Kc value for May is 74%, not 79% like the above chart shows. Last month it was 80%, not 72%.

I had the problem and I worked with Drew and the engineers found the bug in their code and resolved it

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The chart is based on California. Could it be location specific?